BACKGROUND Post-stroke cognitive impairment(PSCI)is not only a common consequence of stroke but also an important factor for adverse prognosis of patients.Biochemical indicators such as blood lipids and blood pressure...BACKGROUND Post-stroke cognitive impairment(PSCI)is not only a common consequence of stroke but also an important factor for adverse prognosis of patients.Biochemical indicators such as blood lipids and blood pressure are affected by many factors,and the ability of evaluating the progress of patients with PSCI is insufficient.Therefore,it is necessary to find sensitive markers for predicting the progress of patients and avoiding PSCI.Recent studies have shown thatβ-amyloid protein 1-42(Aβ1-42)and thyroid hormone levels are closely related to PSCI,which may be the influencing factors of PSCI,but there are few related studies.AIM To investigate the relationship between serum levels of Aβand thyroid hormones in acute stage and PSCI and its predicted value.METHODS A total of 195 patients with acute cerebral infarction confirmed from June 2016 to January 2018 were enrolled in this study.Baseline data and serological indicators were recorded to assess cognitive function of patients.All patients were followed up for 1 year.Their cognitive functions were evaluated within 1 wk,3 mo,6 mo and 1 yr after stroke.At the end of follow-up,the patients were divided into PSCI and non-PSCI according to Montreal cognitive assessment score,and the relationship between biochemical indexes and the progression of PSCI was explored.RESULTS Compared with patients with non-PSCI,the levels of Aβ1-42,triiodothyronine(T3)and free thyroxin were lower in the patients with PSCI.Repeated measures analysis of variance showed that the overall content of Aβ1-42 and T3 in PSCI was also lower than that of the non-PSCI patients.Further analysis revealed that Aβ1-42(r=0.348),T3(r=0.273)and free thyroxin(r=0.214)were positively correlated with disease progression(P<0.05),suggesting that these indicators have the potential to predict disease progression and outcome.Cox regression analysis showed that Aβ1-42 and T3 were important factors of PSCI.Then stratified analysis showed that the lower the Aβ1-42 and T3,the higher risk of PSCI in patients who were aged over 70,female and illiterate.CONCLUSION Aβ1-42 and T3 have the ability to predict the progression of PSCI,which is expected to be applied clinically to reduce the incidence of PSCI and improve the quality of life of patients.展开更多
BACKGROUND: The pharmacological actions of Panax notoginseng saponins (PNS) lie in removing free radicals, anti-inflammation and anti-oxygenation. It can also improve memory and behavior in rat models of Alzheimer’s ...BACKGROUND: The pharmacological actions of Panax notoginseng saponins (PNS) lie in removing free radicals, anti-inflammation and anti-oxygenation. It can also improve memory and behavior in rat models of Alzheimer’s disease. OBJECTIVE: Using the Morris water maze, immunohistochemistry, real-time PCR and RT-PCR, this study aimed to measure improvement in spatial learning, memory, expression of amyloid precursor protein (App) and β-amyloid (Aβ), to investigate the mechanism of action of PNS in the treatment of AD in the senescence accelerated mouse-prone 8 (SAMP8) and compare the effects with huperzine A. DESIGN, TIME AND SETTING: A completely randomized grouping design, controlled animal experiment was performed in the Center for Research & Development of New Drugs, Guangxi Traditional Chinese Medical University from July 2005 to April 2007. MATERIALS: Sixty male SAMP8 mice, aged 3 months, purchased from Tianjin Chinese Traditional Medical University of China, were divided into four groups: PNS high-dosage group, PNS low-dosage group, huperzine A group and control group. PNS was provided by Weihe Pharmaceutical Co., Ltd. (batch No.: Z53021485, Yuxi, Yunan Province, China). Huperzine A was provided by Zhenyuan Pharmaceutical Co., Ltd. (batch No.: 20040801, Zhejiang, China). METHODS: The high-dosage group and low-dosage group were treated with 93.50 and 23.38 mg/kg PNS respectively per day and the huperzine A group was treated with 0.038 6 mg/kg huperzine A per day, all by intragastric administration, for 8 consecutive weeks. The same volume of double distilled water was given to the control group. MAIN OUTCOME MEASURES: After drug administration, learning and memory abilities were assessed by place navigation and spatial probe tests. The recording indices consisted of escape latency (time-to-platform), and the percentage of swimming time spent in each quadrant. The number of Aβ1-40, Aβ1-42 and App immunopositive neurons in the brains of SAMP8 mice was analyzed by immunohistochemistry. The mRNA content of App, tau, acetylcholinesterase, and synaptophysin (Syp) was tested by real time PCR and RT-PCR. RESULTS: The PCR results show that PNS can downregulate the expression of the App gene and upregulate the expression of the Syp gene in the parietal cortex and hippocampus of SAMP8 mice. The therapeutic effects of the PNS high-dosage group were greater than those of the PNS low-dosage group and the huperzine A group (P < 0.05). The results of the Morris water maze and immunohistochemistry indicated that PNS can improve the capacity for spatial learning and memory in SAMP8 mice, and reduce the content of Aβ1-40, Aβ1-42 and expression of App in the brains of SAMP8 mice. The therapeutic effects of the PNS high-dosage group were greater than that of the PNS low-dosage group and the huperzine A group (P < 0.05). CONCLUSION: These results support the hypothesis that PNS plays a therapeutic and protective role on the pathological lesions and learning dysfunction of Alzheimer’s disease. The therapeutic effects of PNS for Alzheimer’s disease are possibly achieved through downregulating the expression of the App gene and upregulating the expression of the Syp gene. The therapeutic effects of PNS are dose-dependent and are greater than the effect of huperzine A.展开更多
Alzheimer's disease is pathologically defined by accumulation of extracellular amyloid-β(Aβ). Approximately 25 mutations in β-amyloid precursor protein(APP) are pathogenic and cause autosomal dominant Alzheimer...Alzheimer's disease is pathologically defined by accumulation of extracellular amyloid-β(Aβ). Approximately 25 mutations in β-amyloid precursor protein(APP) are pathogenic and cause autosomal dominant Alzheimer's disease. To date, the mechanism underlying the effect of APP mutation on Aβ generation is unclear. Therefore, investigating the mechanism of APP mutation on Alzheimer's disease may help understanding of disease pathogenesis. Thus, APP mutations(A673T, A673 V, E682 K, E693 G, and E693Q) were transiently co-transfected into human embryonic kidney cells. Western blot assay was used to detect expression levels of APP, beta-secretase 1, and presenilin 1 in cells. Enzyme-linked immunosorbent assay was performed to determine Aβ_(1–40) and Aβ_(1–42) levels. Liquid chromatography-tandem mass chromatography was used to examine VVIAT, FLF, ITL, VIV, IAT, VIT, TVI, and VVIA peptide levels. Immunofluorescence staining was performed to measure APP and early endosome antigen 1 immunoreactivity. Our results show that the protective A673 T mutation decreases Aβ_(42)/Aβ_(40) rate by downregulating IAT and upregulating VVIA levels. Pathogenic A673 V, E682 K, and E693 Q mutations promote Aβ_(42)/Aβ_(40) rate by increasing levels of CTF99, Aβ_(42), Aβ_(40), and IAT, and decreasing VVIA levels. Pathogenic E693 G mutation shows no significant change in Aβ_(42)/Aβ_(40) ratio because of inhibition of γ-secretase activity. APP mutations can change location from the cell surface to early endosomes. Our findings confirm that certain APP mutations accelerate Aβ generation by affecting the long Aβ cleavage pathway and increasing Aβ_(42/40) rate, thereby resulting in Alzheimer's disease.展开更多
BACKGROUND:During onset and development of Alzheimer's disease,β-amyloid(Aβ) precursor protein(APP),β-site amyloid precursor protein cleaving enzyme(BACE),andβ-amyloid are key genes and proteins in the Aβpath...BACKGROUND:During onset and development of Alzheimer's disease,β-amyloid(Aβ) precursor protein(APP),β-site amyloid precursor protein cleaving enzyme(BACE),andβ-amyloid are key genes and proteins in the Aβpathway,and over-expression of these genes can lead to Aβdeposition in the brain. OBJECTIVE:To observe the influence of Longyanshen polysaccharides on expression of BACE, APP,and Aβin the senescence-accelerated mouse prone/8(SAMP8) brain,and to compare these effects with huperzine A treatment. DESIGN,TIME AND SETTING:A randomized,controlled,neurobiochemical experiment was performed at the Department of Pharmacology and Scientific Experimental Center of Guangxi Medical University from September 2005 to January 2008. MATERIALS:Longyanshen polysaccharides powder was extracted from the dried slices of the medicinal plant Longyanshen.The active component,Longyanshen polysaccharides,was provided by the Department of Pharmacology,Guangxi Medical University;huperzine A was purchased from Yuzhong Drug Manufactory,China. METHODS:Healthy SAMP8 mice were used to establish a model of Alzheimer's disease.A total of 50 SAMP8 mice were randomly assigned to 5 groups(n = 10):SAMP8,huperzine A,low-,middle-, and high-dose polysaccharides.In addition,10 senescence-accelerated mouse resistant 1(SAMR1) mice were selected as normal controls.SAMP8 and SAMR1 mice were administered 30 mL/kg normal saline;the huperzine A group was administered 0.02 mg/kg huperzine A;the low-,middle-, and high-dose polysaccharides groups were respectively administered 45,90,and 180 mg/kg Longyanshen polysaccharides.Each group was treated by intragastric administration,once per day, for 50 consecutive days. MAIN OUTCOME MEASURES:One hour after the final administration,immunohistochemical analysis was used to determine Aβexpression in the cortex and hippocampus of SAMP8 mice. Reverse-transcription polymerase chain reaction was used to determine mRNA levels of BACE and APP in SAMP8 brain tissue. RESULTS:Compared with the SAMR1 group,Aβexpression in the cerebral cortex and hippocampus,as well as expression of BACE,APP mRNA in the brain was significantly increased in the SAMP8 group(P<0.05-0.01).Compared with the SAMP8 group,Aβexpression,as well as BACE and APP mRNA expression,were significantly decreased in the cerebral cortex and hippocampus of huperzine A and low-,middle-,and high-dose polysaccharides groups(P<0.05-0.01).In particular,the effect of high-dose polysaccharides was the most significant(P<0.05-0.01). CONCLUSION:Longyanshen polysaccharides reduced or inhibited over-expression of BACE,APP, and Aβin SAMP8 mice in a dose-dependent manner,and the effect was not worse than huperzine A.展开更多
Objective To investigate the effects of the total saponin of Dipsacus asperoides (tSDA) and ginsenoside Rb1 (GRb1) on the apoptosis of primary cultured hippocampal neurons induced by β-amyloid protein (Aβ). Methods ...Objective To investigate the effects of the total saponin of Dipsacus asperoides (tSDA) and ginsenoside Rb1 (GRb1) on the apoptosis of primary cultured hippocampal neurons induced by β-amyloid protein (Aβ). Methods Primary cultured hippocampal neurons, the cultures were pretreated with tSDA and GRb1 on 10d for 24 hours respectively. Then the cultures were treated with 35 μmol·L -1 Aβ25-35 for 24 hours, observed the changing of survival rate of neurons and the apoptosis of neurons with biochemical analysis combining immunofluorescent cytochemical double-staining technique. Results Hippocampal neurons were treated with 35 μmol·L -1 Aβ for 24 hours, and survival rate of neurons downed to 52.6%. When neurons were pretreated by tSDA and GRb1, survival rate of neurons increased 11% to 15%. The findings of immunofluorescent cytochemical double-staining indicated that apoptotic neurons were obviously more than that of the blank group, reaching 43.9%.When neurons were pretreated by tSDA and GRb1, apoptotic neurons were downed to 16.6%, 10.8% respectively. Conclusion tSDA had the same effects as GRb1, protecting the neurons, antagonizing neurotoxicity of Aβ, increasing survival rate of neurons, and reducing apoptotic neurons induced by Aβ.展开更多
Previous studies have reported that non-human primates and rodents exposed to lead during brain development may become dependent on the deposition of pre-determined β-amyloid protein (Aβ),and exhibit upregulation of...Previous studies have reported that non-human primates and rodents exposed to lead during brain development may become dependent on the deposition of pre-determined β-amyloid protein (Aβ),and exhibit upregulation of β-site amyloid precursor protein expression in old age.However,further evidence is required to elucidate the precise relationship and molecular mechanisms underlying the effects of early lead exposure on excessive Aβ production in adult mammals.The present study investigated the effects of lead exposure on expression of β-amyloid precursor protein cleavage enzyme-1 (BACE-1) in the rat retina and the production of Aβ in early development,using the retina as a window for studying Alzheimer's disease.Adult rats were intraocularly injected with different doses of lead acetate (10μmol/L,100μmol/L,1 mmol/L,10 mmol/L and 100 mmol/L).The results revealed that retinal lead concentration,BACE-1 and its cleavage products β-C-terminal fragment and retina Aβ1-40 were all significantly increased in almost all of the lead exposure groups 48 hours later in a dose-dependent manner.The only exception was the 10μmol/L group.The distribution of BACE-1 in the retina did not exhibit obvious changes,and no distinctive increase in the activation of retinal microglia was apparent.Similarly,retinal synaptophysin expression did not exhibit any clear changes.These data suggest that lead exposure can result in the upregulation of retinal neuron BACE-1 expression in the early period of development and further increase the overproduction of Aβ1-40 in the retina.Our results provided novel insight into the molecular mechanisms underlying environmentally-induced Alzheimer's disease.展开更多
BACKGROUND:Modern pharmacological studies have shown that Ginsenoside Rg1 is one of the active components of ginseng that promote intelligence in the nervous system.Ginsenoside Rg1 can improve memory and learning in m...BACKGROUND:Modern pharmacological studies have shown that Ginsenoside Rg1 is one of the active components of ginseng that promote intelligence in the nervous system.Ginsenoside Rg1 can improve memory and learning in mouse models ofβ-amyloid protein(Aβ)-induced dementia. OBJECTIVE:To investigate whether effects of Ginsenoside Rg1 against Aβare associated with activity of nuclear factor-kappa B(NF-κB). DESIGN,TIME AND SETTING:The randomized,controlled,cell biological experiment was performed at the DME Center,Institute of Clinical Pharmacology,Guangzhou University of Chinese Medicine,China from July 2005 to May 2006. MATERIALS:Beta-amyloid fragment 25-35(Aβ_(25-35)) was supplied by the Neural Biochemical Laboratory,Xuanwu Hospital,Capital Medical University,China.Ginsenoside Rg1 was obtained from National Institute for the Control of Pharmaceutical and Biological Products,China.Rabbit anti-rat NF-κB p65 antibody was purchased from Santa Cruz Biotechnology,USA. METHODS:Hippocampal neurons and cortical astrocytes of neonatal Sprague Dawley rats were harvested and treated with various concentrations(0,5,10,20,and 40μmol/L) of Aβfor 6,12,and 24 hours to establish cellular models of Alzheimer's disease.Cellular models were pretreated with various concentrations of Ginsenoside Rg1(1,2,4,8,and 16μmol/L).According to cell morphology and activity,the following conditions were selected:40μmol/L Aβfor 24 hours,as well as 2,4,and 8μmol/L Ginsenoside Rg1.NF-κB activity was observed using immunofluorescence and cytochemical staining. MAIN OUTCOME MEASURES:Morphology and viability of hippocampal neurons and cortical astrocytes,and activities of NF-κB were measured. RESULTS:Hippocampal neuron activity was significantly greater in the normal and 2 and 4μmol/L Ginsenoside Rg1 groups compared with the model group(P<0.05).Astrocyte activity was significantly greater in the normal,1,2,4,8,and 16μmol/L Ginsenoside Rg1 groups compared with the model group(P<0.05).NF-κB activity of hippocampal neurons was significantly greater in the normal,2,4,and 8μmol/L Ginsenoside Rg1 groups compared with the model group(P<0.01). NF-κB activity of astrocytes was significantly less in the normal,2,4,and 8μmol/L Ginsenoside Rg1 groups compared with the model group(P<0.01 or P<0.05).No significant difference in NF-κB activity was determined between the 2μmol/L Ginsenoside Rg1 and normal groups(P>0.05). CONCLUSION:Ginsenoside Rg1 protected neural cells by upregulating NF-κB activity in neurons and downregulating NF-κB activity in astrocytes.Ginsenoside Rg1(2μmol/L) maintained cell activity and NF-κB activity at normal levels.展开更多
Curcumin exerts a neuroprotective effect on Alzheimer’s disease;however,it is not known whether microRNAs are involved in this protective effect.This study was conducted using swAPP695-HEK293 cells as an Alzheimer’s...Curcumin exerts a neuroprotective effect on Alzheimer’s disease;however,it is not known whether microRNAs are involved in this protective effect.This study was conducted using swAPP695-HEK293 cells as an Alzheimer’s disease cell model.swAPP695-HEK293 cells were treated with 0,0.5,1,2,5,and 10μM curcumin for 24 hours.The changes in miR-15b-5p,miR-19a-3p,miR-195-5p,miR-101-3p,miR-216b-5p,miR-16-5p and miR-185-5p expression were assessed by real-time quantitative polymerase chain reaction.The mRNA and protein levels of amyloid precursor protein,amyloid-β40 and amyloid-β42 were evaluated by quantitative real-time polymerase chain reaction,western blot assays and enzyme-linked immunosorbent assays.swAPP695-HEK293 cells were transfected with miR-15b-5p mimic,or treated with 1μM curcumin 24 hours before miR-15b-5p inhibitor transfection.The effects of curcumin on amyloid precursor protein,amyloid-β40 and amyloid-β42 levels were evaluated by western blot assays and enzyme-linked immunosorbent assay.Luciferase assays were used to analyze the interaction between miR-15b-5p and the 3′-untranslated region of amyloid precursor protein.The results show that amyloid precursor protein and amyloid-βexpression were enhanced in swAPP695-HEK293 cells compared with HEK293 parental cells.Curcumin suppressed the expression of amyloid precursor protein and amyloid-βand up-regulated the expression of miR-15b-5p in swAPP695-HEK293 cells.In addition,we found a negative association of miR-15b-5p expression with amyloid precursor protein and amyloid-βlevels in the curcumin-treated cells.Luciferase assays revealed that miR-15b-5p impaired the luciferase activity of the plasmid harboring the 3′-untranslated region of amyloid precursor protein.These findings indicate that curcumin down-regulates the expression of amyloid precursor protein and amyloid-βin swAPP695-HEK293 cells,which was partially mediated by miR-15b-5p via targeting of the 3′-untranslated region of amyloid precursor protein.展开更多
After binding to the estrogen receptor, estrogen can alleviate the toxic effects of beta-amyloid protein, and thereby exert a therapeutic effect on Alzheimer's disease patients. Estrogen can increase the incidence...After binding to the estrogen receptor, estrogen can alleviate the toxic effects of beta-amyloid protein, and thereby exert a therapeutic effect on Alzheimer's disease patients. Estrogen can increase the incidence of breast carcinoma and endometrial cancer in post-menopausal women, so it is not suitable for clinical treatment of Alzheimer's disease. There is recent evidence that the estrogen receptor can exert its neuroprotective effects without estrogen dependence. Real-time quantitative PCR and flow cytometry results showed that, compared with non-transfected PC12 cells, adenovirus-mediated estrogen receptor β gene-transfected PC12 cells exhibited lower expression of tumor necrosis factor α and interleukin 1β under stimulation with beta-amyloid protein and stronger protection from apoptosis. The Akt-specific inhibitor Abi-2 decreased the anti-inflammatory and anti-apoptotic effects of estrogen receptor β gene-transfection. These findings suggest that overexpression of estrogen receptor β can alleviate the toxic effect of beta-amyloid protein on PC12 cells, without estrogen dependence. The Akt pathway is one of the potential means for the anti-inflammatory and anti-apoptotic effects of the estrogen receptor.展开更多
BACKGROUND: To evaluate and summarize the effects of cerebral perfusion and vascular reserve on the treatment of SICAS. Recently, research on β-amyloid protein has focused on the regulatory effects of es- trogen or p...BACKGROUND: To evaluate and summarize the effects of cerebral perfusion and vascular reserve on the treatment of SICAS. Recently, research on β-amyloid protein has focused on the regulatory effects of es- trogen or phytoestrogen on its deposition. However, there have been only a few reports on dynamic changes of β-amyloid protein deposition in hippocampus of ovariectomized rats. OBJECTIVE: To measureβ-amyloid protein deposition in the hippocampal formation of ovariectomized rats by using immunohistochemistry; to observe time-dependent dynamic changes. DESIGN: Randomized controlled animal study. SETTING: Third Xiangya Hospital of Central South University. MATERIALS: The experiment was carried out in the Central Laboratory of the Third Xiangya Hospital of Central South University from November 2005 to December 2006. Fifty healthy female Sprague Dawley (SD) rats, weighing (293 ± 10) g, were provided by the Animal Laboratory of Xiangya Medical College, Central South University. All rats had neither a childbearing history nor hepatic or renal disease, or skeletal deformity. β-amyloid protein immunohistochemical kit was provided by Wuhan Boster Company. The ex- periment was in accordance with animal ethics standards. METHODS: All rats were randomly divided into five groups, including normal control group (n = 10), sham operation group (n = 10), and ovariectomized group (n = 30). After anesthesia in the ovariectomized group, the bilateral ovaries were separated and resected. The same volume of fat was resected in the sham operation group. Rats from the normal control group, however, did not receive any surgical treatments. Rats in the normal control group and sham operation group were sacrificed by anesthesia 7 weeks after surgery. Every ten rats from the ovariectomized group was respectively sacrificed at 7, 15, and 30 weeks after surgery. Immunohistochemistry was used to detectβ-amyloid protein deposition in hippocampal sections. Cell counting and gray value measurements served to record the dynamic changes in β-amyloid protein deposi- tion. MAIN OUTCOME MEASURES: ① Morphological changes. ② Positive cell counts from β-amyloid protein stainings and gray value measurements. RESULTS: All 50 rats were involved in the final analysis. ① Morphological changes. β-amyloid-positive cells were detected in the hippocampus of all rats. Biebrich scarlet stained neurites with a swollen cytoplasm. A few β-amyloid-positive cells were observed in all groups 7 weeks after surgery, and plasma and neurites were slightly stained. By 15 weeks after surgery, a number of β-amyloid-positive cells were observed in the ovariectomized group, and plasma and neurites were also slightly stained. By 30 weeks after surgery, how- ever, many β-amyloid-positive cells were observed in the ovariectomized group. These cells were partially aggregated and darkly stained. ② Positive cell counts and gray value of β-amyloid protein in hippocam- pus. At 7 weeks after surgery, cell counts and gray value measurements were not significantly different in the ovariectomized group compared to the sham operation group and normal control group (P > 0.05). Cell counts and gray value measurements were higher in the ovariectomized group by 15 weeks compared to those by 7 weeks in the normal control group, sham operation group and ovariectomized group (P < 0.05). At 30 weeks after surgery, cell counts and gray value measurements were higher in the ovariectomized group compared to the normal control group. In addition, there were significant differences between sham opera- tion group and ovariectomized group at 7 and 15 weeks after operation (P < 0.05-0.01). Cell counts and gray value measurements increased in all groups over time. CONCLUSION: Extended estrogen deficiency in rats can increase β-amyloid protein deposition in the hippocampus and the deposition increases over time.展开更多
Objective To explore the effect of β-amyloid protein (Aβ) on S100β expression in rat hippocampus and its mechanisms. Methods At 7 days after bilateral stereotaxis injection of different dose of fibrillar Aβ 25-35 ...Objective To explore the effect of β-amyloid protein (Aβ) on S100β expression in rat hippocampus and its mechanisms. Methods At 7 days after bilateral stereotaxis injection of different dose of fibrillar Aβ 25-35 and interluekin-1 receptor antagonist (IL-1ra) into the rat CA1 region, the learning and memory abilities of rats were tested with passive avoidance task. Amyloid deposition was detected by using Congo red staining technique. Nissl staining and immunohistochemical techniques were used to analyze the number of neurons, and GFAP and the S100β expression in hippocampal CA1 region , respectively. Results After fibrillar Aβ injection, the step-through latency of rats was significantly shortened compared to that of the control group. The GFAP positive astrocytes were found surrounding amyloid deposition. Neuronal loss occurred in the pyramidal cell layer of CA1 region. The number of S100β positive cells in Aβ-treated group was significantly increased compared with that in the control group. After IL-1ra injection, the number of S100β positive cells was significantly decreased. Conclusion Intrahippocampal injection of Aβ 25-35 could cause similar pathologic changes of Alzheimer's disease. Aβ 25-35 was capable of up-regulating S100β expression in a dose-dependent manner. The injection of IL-1ra could attenuate the effect of Aβ on S100β expression.展开更多
Aim: The abnormal accumulation, assembly and deposition of the amyloid β-protein (Aβ) are prominent pathological features of patients with Alzheimer’s disease (AD) and related disorders. A number of factors in the ...Aim: The abnormal accumulation, assembly and deposition of the amyloid β-protein (Aβ) are prominent pathological features of patients with Alzheimer’s disease (AD) and related disorders. A number of factors in the brain can influence Aβ accumulation and associated pathologies. The aim of the present study was to determine the consequences of deleting nitric oxide synthase (NOS) 3, the endothelial form of NOS, in Tg-5xFAD mice, a model of parenchymal AD-like amyloid pathology. Methods: Tg-5xFAD mice were bred with NOS3-/- mice. Cohorts of Tg-5xFAD mice and bigenic Tg-5xFAD/NOS3-/- mice were aged to six months followed by collection of the blood and brain tissues from the mice for biochemical and pathological analyses. Results: ELISA analyses show that the absence of NOS3 results in elevated levels of cerebral and plasma Aβ peptides in Tg-5xFAD mice. Immunohistochemical analyses show that the absence of NOS3 increased the amount of parenchymal Aβ deposition and fibrillar amyloid accumulation in Tg-5xFAD mice. The elevated levels of Aβ were not due to changes in the expression levels of transgene encoded human amyloid precursor protein (APP), endogenous β-secretase, or increased proteolytic processing of APP. Conclusions: The results from this study suggest that the loss of NOS3 activity enhances Aβ pathology in Tg-5xFAD mice. These findings are similar to previous studies of NOS2 deletion suggesting that reduced NOS activity and NO levels enhance amyloid-associated pathologies in human APP transgenic mice.展开更多
Previous studies indicate that memantine, a low-affinity N-methyl-D-aspartate receptor antagonist, exerted acute protective effects against amyloid-β protein-induced neurotoxicity. In the present study, the chronic e...Previous studies indicate that memantine, a low-affinity N-methyl-D-aspartate receptor antagonist, exerted acute protective effects against amyloid-β protein-induced neurotoxicity. In the present study, the chronic effects and mechanisms of memantine were investigated further using electrophysiological methods. The results showed that 7-day intraperitoneal application of memantine, at doses of 5 mg/kg or 20 mg/kg, did not alter hippocampal long-term potentiation induction in rats, while 40 mg/kg memantine presented potent long-term potentiation inhibition. Then further in vitro studys were carried out in 5 mg/kg and 20 mg/kg memantine treated rats. We found that 20 mg/kg memantine attenuated the potent long-term potentiation inhibition caused by exposure to amyloid-β protein in the dentate gyrus in vitro. These findings are the first to demonstrate the antagonizing effect of long-term systematic treatment of memantine against amyloid-β protein triggered long-term potentiation inhibition to improve synaptic plasticity.展开更多
BACKGROUND:Previous studies have demonstrated that Piper futokadsura stem selectively inhibits expression of amyloid precursor protein(APP) at the mRNA level.In addition,the piperlonguminine(A) and dihydropiperlongumi...BACKGROUND:Previous studies have demonstrated that Piper futokadsura stem selectively inhibits expression of amyloid precursor protein(APP) at the mRNA level.In addition,the piperlonguminine(A) and dihydropiperlonguminine(B) components(1:0.8),which can be separated from Futokadsura stem,selectively inhibit expression of the APP at mRNA and protein levels. OBJECTIVE:Based on previous findings,the present study investigated the effects ofβ-site amyloid precursor protein cleaving enzyme(BACE1) and APP genes on the production ofβ-amyloid peptide 42(Aβ42) in human neuroblastoma cells(SK-N-SH cells) using small interfering RNAs (siRNAs) and A/B components separated from Futokadsura stem,respectively. DESIGN,TIME AND SETTING:A gene interference-based randomized,controlled,in vitro experiment was performed at the Key Laboratory of Cardiovascular Remodeling and Function Research,Ministries of Education and Public Health,and Institute of Pharmacologic Research, School of Pharmaceutical Science & Department of Biochemistry,School of Medicine,Shandong University between July 2006 and December 2007. MATERIALS:SK-N-SH cells were provided by Shanghai Institutes of Biological Sciences,Chinese Academy of Sciences,Shanghai,China;mouse anti-human BACE1 monoclonal antibody was purchased from R&D Systems,USA;mouse anti-human APP monoclonal antibody was purchased from Cell Signaling Technology,USA;and horseradish peroxidase(HRP)-conjugated goat anti-mouse IgG was provided by Sigma,USA. METHODS:The human BACE1 cDNA sequence was obtained from NCBI website (www.ncbi.nlm.nih.gov/sites/entrez).Three pairs of siRNAs,specific to human BACE1 gene,were synthesized through the use of Silencer^(?) pre-designed siRNA specification,and were transfected into SK-N-SH cells with siPORT NeoFX transfection agent to compare the effects of different concentrations of siRNAs(10-50 nmol/L) on SK-N-SH cells.Futokadsura stem was separated and purified with chemical methods,and the crystal was composed of A/B components,with an A to B ratio of 1:0.8.The A/B(1:0.8) components were added to the SK-N-SH cells at different concentrations(13.13,6.56,and 3.28 mg/mL). MAIN OUTCOME MEASURES:Using RT-PCR and Western blot methods,BACE1 and APP expression at mRNA and protein levels was detected in SK-N-SH cells following treatment with different siRNAs and concentrations of Futokadsura stem-separated A/B components,respectively. Altered Aβ42 secretion by SK-N-SH cells was determined by ELISA. RESULTS:BACE1 mRNA and protein levels were significantly suppressed by 40 and 50 nmol/L siRNAs at 48 hours post-transfection.A/B components(1:0.8),which were separated from Futokadsura stem,selectively inhibited mRNA and protein expression of APP in SK-N-SH cells. Aβ42 secretion by SK-N-SH cells was significantly decreased following treatment with siRNAs or A/B components. CONCLUSION:Inhibition of BACE1 and APP genes by various materials and methods efficiently decreased production of Aβ42.展开更多
BACKGROUND: Studies have shown that scorpion venom heat-resistant protein (SVHRP) exhibitsprotective effects on primary cultured hippocampal neurons.OBJECTIVE: To determine the effects of SVHRP on astrocyte activity a...BACKGROUND: Studies have shown that scorpion venom heat-resistant protein (SVHRP) exhibitsprotective effects on primary cultured hippocampal neurons.OBJECTIVE: To determine the effects of SVHRP on astrocyte activity and synaptic density in thehippocampus induced by amyloid β peptide 1-40 (Aβ_(1-40)) neurotoxicity.DESIGN, TIME AND SETTING: The randomized, controlled, animal experiment was performed atthe Central Laboratory, the Laboratory of Human Anatomy, and the Laboratory of Physiology, inDalian Medical University between March 2006 and June 2008.MATERIALS: Aβ_(1-40) was provided by Biosource, USA; SVHRP was a patented biological product ofDalian Medical University (No. ZL01 1 06166.9).METHODS: A total of 27 healthy, 2-month-old, male SD rats were randomly assigned to 3 groups:control, Aβ, and SVHRP, with 9 rats in each group. Alzheimer's disease was simulated with 10 μgAβ_(1-40) bilaterally injected into the hippocampus of the Aβ and SVHRP groups. The control group wasinjected with 2 μL 0.05% trifluoroacetic acid. One day following model establishment, the SVHRPgroup received an intraperitoneal injection of 2 μg/100 g SVHRP, while the control group and Aβgroup received 0.5 mL/100 g tri-distilled water, once per day, for 10 consecutive days.MAIN OUTCOME MEASURES: At 16 days following model establishment, synaptophysin (p38)expression in CA1 CA4 regions of the rat hippocampus was determined by immunohistochemistry.Glial fibrillary acidic protein (GFAP) expression surrounding the hippocampal Aβ_(1-40) injected areawas also detected. At 11 days following model establishment, escape latency, swimming time, anddistance to target quadrant were measured using the Morris water maze.RESULTS: Compared with the control group, the Aβ group exhibited notably reduced p38expression (P < 0.05) and notably increased GFAP expression in the rat hippocampus (P < 0.05).Water maze results demonstrated that escape latency was prolonged (P < 0.05), and swimming timeand distance to the target quadrant were shortened in the Aβ group. Compared with the Aβ group,the SVHRP group exhibited notably increased p38 expression (P < 0.05) and notably decreasedGFAP expression in the rat hippocampus (P < 0.05). Water maze results demonstrated that escapelatency was significantly reduced (P < 0.05), and swimming time and distance to the target quadrantwere significantly prolonged.CONCLUSION: SVHRP inhibited exogenous Aβ_(1-40)-induced astrocyte activation and synapticdensity decline in the rat hippocampus. Place navigation and spatial searching results showed thatSVHRP blocked Aβ_(1-40)-induced impaired learning and memory.展开更多
BACKGROUND: Tongxinluo has been clinically proven to be effective in improving memory and cognitive function in patients with post-stroke vascular dementia. Is the mechanism related to the deposition of beta-amyloid p...BACKGROUND: Tongxinluo has been clinically proven to be effective in improving memory and cognitive function in patients with post-stroke vascular dementia. Is the mechanism related to the deposition of beta-amyloid peptide (Aβ) in hippocampus? OBJECTIVE: To observe the effect of Tongxinluo on cognitive impairment in a mouse model with vascular dementia and the changes of Aβ deposition andβ-secretase 1 (BACE1) expression. DESIGN: Randomized controlled study. SETTING: State Key Laboratory of Pharmaceutical Biotechnology of Nanjing University and Affiliated Drum Tower Hospital of Nanjing University Medical School. MATERIALS: The experiment was carried out in the State Key Laboratory of Pharmaceutical Biotechnology of Nanjing University and Affiliated Drum Tower Hospital of Nanjing University Medical School from March 2006 to January 2007. A total of 36 healthy Kunming mice, 18 of each gender, were chosen. The study was conducted in accordance with the National Regulations of Experimental Animal Administration, and all animal experiments were approved by the Committee of Experimental Animal Administration of Nanjing University. Tongxinluo was provided by Shijiazhuang Yiling Pharmaceutical Co., Ltd. METHODS: All mice were randomly divided into 6 groups, including naive control (n=6), sham-operated control (n=6) and experimental groups treated with different doses of Tongxinluo (0.2, 0.4, and 0.6 g/kg/d; n=6 for each group) or vehicle (n=6). Five groups were subjected to bilateral common carotid arteries (2-VO) occlusion to produce a vascular dementia model (no occlusion was performed in sham-operated group). The mice in the Tongxinluo treatment groups were intragastricly administered daily with a Tongxinluo suspension (40 g/L in distilled water) at doses of 0.2, 0.4 or 0.6 g/kg/d from day 1 to day 30 post-surgery. The animals in vehicle, sham-operated and naive groups were administered an equal volume of distilled water. MAIN OUTCOME MEASURES: ①Escape latency time determined in all groups of mice before and after 2-VO occlusion by Morris water maze. ②Changes in BACE1 mRNA expression in the hippocampi of mice among the six groups by RT-PCR assay, and BACE1 and Aβ protein expression in the hippocampi of mice by Western blot. RESULTS: All 36 mice were involved in the final analysis. ① No difference was detected in escape latency time to a hidden platform among all groups in water maze test before surgery (P > 0.05) At 30 days after 2-VO occlusion, the vehicle animals exhibited a significantly longer latency in finding the hidden platform compared to that of sham-operated and naive animals (P < 0.01). The prolonged escape latency was significantly reduced by oral administration of 0.4 g or 0.6 kg/day (P < 0.01, P < 0.05). BACE1 mRNA and protein expression in vehicle animals were much higher than in sham-operated and naive animals (P < 0.01). The ischemia-induced increases in BACE1 mRNA and protein level were attenuated by all three doses of Tongxinluo treatment (P < 0.01), and the 0.4 g/kg/d treatment was the most effective. Aβ protein expression in vehicle animals after 2-VO occlusion were much higher than in sham-operated and na?ve animals (P < 0.01). 2-VO occlusion-induced Aβ generation was significantly attenuated by all doses of Tongxinluo treatment, with the most effective dose being 0.4 g/kg/d (P < 0.01). CONCLUSION: BACE1 mRNA levels and protein levels of BACE1 and Aβare reduced in the hippocampi of vascular dementia model mice by all three doses of Tongxinluo treatment, with the most effective dose being 0.4 g/kg/d. The results suggest that inhibition of post-ischemia BACE1 expression and Aβ generation in brain might underlie Tongxinluo’s effects in improving cognitive impairment.展开更多
基金Supported by Science and Technology Support Projects in Biomedicine Field of Shanghai Science and Technology Commission,No.19441907500Naval Medical University Military Medical Innovation,No.2017JS07Science and Technology Action Innovation Program by Science and Technology Commission of Shanghai,No.17411950104
文摘BACKGROUND Post-stroke cognitive impairment(PSCI)is not only a common consequence of stroke but also an important factor for adverse prognosis of patients.Biochemical indicators such as blood lipids and blood pressure are affected by many factors,and the ability of evaluating the progress of patients with PSCI is insufficient.Therefore,it is necessary to find sensitive markers for predicting the progress of patients and avoiding PSCI.Recent studies have shown thatβ-amyloid protein 1-42(Aβ1-42)and thyroid hormone levels are closely related to PSCI,which may be the influencing factors of PSCI,but there are few related studies.AIM To investigate the relationship between serum levels of Aβand thyroid hormones in acute stage and PSCI and its predicted value.METHODS A total of 195 patients with acute cerebral infarction confirmed from June 2016 to January 2018 were enrolled in this study.Baseline data and serological indicators were recorded to assess cognitive function of patients.All patients were followed up for 1 year.Their cognitive functions were evaluated within 1 wk,3 mo,6 mo and 1 yr after stroke.At the end of follow-up,the patients were divided into PSCI and non-PSCI according to Montreal cognitive assessment score,and the relationship between biochemical indexes and the progression of PSCI was explored.RESULTS Compared with patients with non-PSCI,the levels of Aβ1-42,triiodothyronine(T3)and free thyroxin were lower in the patients with PSCI.Repeated measures analysis of variance showed that the overall content of Aβ1-42 and T3 in PSCI was also lower than that of the non-PSCI patients.Further analysis revealed that Aβ1-42(r=0.348),T3(r=0.273)and free thyroxin(r=0.214)were positively correlated with disease progression(P<0.05),suggesting that these indicators have the potential to predict disease progression and outcome.Cox regression analysis showed that Aβ1-42 and T3 were important factors of PSCI.Then stratified analysis showed that the lower the Aβ1-42 and T3,the higher risk of PSCI in patients who were aged over 70,female and illiterate.CONCLUSION Aβ1-42 and T3 have the ability to predict the progression of PSCI,which is expected to be applied clinically to reduce the incidence of PSCI and improve the quality of life of patients.
基金the National Natural Science Foundation of China, No: 30560189
文摘BACKGROUND: The pharmacological actions of Panax notoginseng saponins (PNS) lie in removing free radicals, anti-inflammation and anti-oxygenation. It can also improve memory and behavior in rat models of Alzheimer’s disease. OBJECTIVE: Using the Morris water maze, immunohistochemistry, real-time PCR and RT-PCR, this study aimed to measure improvement in spatial learning, memory, expression of amyloid precursor protein (App) and β-amyloid (Aβ), to investigate the mechanism of action of PNS in the treatment of AD in the senescence accelerated mouse-prone 8 (SAMP8) and compare the effects with huperzine A. DESIGN, TIME AND SETTING: A completely randomized grouping design, controlled animal experiment was performed in the Center for Research & Development of New Drugs, Guangxi Traditional Chinese Medical University from July 2005 to April 2007. MATERIALS: Sixty male SAMP8 mice, aged 3 months, purchased from Tianjin Chinese Traditional Medical University of China, were divided into four groups: PNS high-dosage group, PNS low-dosage group, huperzine A group and control group. PNS was provided by Weihe Pharmaceutical Co., Ltd. (batch No.: Z53021485, Yuxi, Yunan Province, China). Huperzine A was provided by Zhenyuan Pharmaceutical Co., Ltd. (batch No.: 20040801, Zhejiang, China). METHODS: The high-dosage group and low-dosage group were treated with 93.50 and 23.38 mg/kg PNS respectively per day and the huperzine A group was treated with 0.038 6 mg/kg huperzine A per day, all by intragastric administration, for 8 consecutive weeks. The same volume of double distilled water was given to the control group. MAIN OUTCOME MEASURES: After drug administration, learning and memory abilities were assessed by place navigation and spatial probe tests. The recording indices consisted of escape latency (time-to-platform), and the percentage of swimming time spent in each quadrant. The number of Aβ1-40, Aβ1-42 and App immunopositive neurons in the brains of SAMP8 mice was analyzed by immunohistochemistry. The mRNA content of App, tau, acetylcholinesterase, and synaptophysin (Syp) was tested by real time PCR and RT-PCR. RESULTS: The PCR results show that PNS can downregulate the expression of the App gene and upregulate the expression of the Syp gene in the parietal cortex and hippocampus of SAMP8 mice. The therapeutic effects of the PNS high-dosage group were greater than those of the PNS low-dosage group and the huperzine A group (P < 0.05). The results of the Morris water maze and immunohistochemistry indicated that PNS can improve the capacity for spatial learning and memory in SAMP8 mice, and reduce the content of Aβ1-40, Aβ1-42 and expression of App in the brains of SAMP8 mice. The therapeutic effects of the PNS high-dosage group were greater than that of the PNS low-dosage group and the huperzine A group (P < 0.05). CONCLUSION: These results support the hypothesis that PNS plays a therapeutic and protective role on the pathological lesions and learning dysfunction of Alzheimer’s disease. The therapeutic effects of PNS for Alzheimer’s disease are possibly achieved through downregulating the expression of the App gene and upregulating the expression of the Syp gene. The therapeutic effects of PNS are dose-dependent and are greater than the effect of huperzine A.
基金funded by the National Natural Science Foundation of China,No.81671268(to HQ)partially supported by a grant from the Ministry of Science and Technology of China,No.2013YQ03059514(to HQ)a grant from Key Laboratory for Neurodegenerative Disease of Ministry of Education of China,No.2015SJBX05(to HQ),2015SJZS01(to HQ)
文摘Alzheimer's disease is pathologically defined by accumulation of extracellular amyloid-β(Aβ). Approximately 25 mutations in β-amyloid precursor protein(APP) are pathogenic and cause autosomal dominant Alzheimer's disease. To date, the mechanism underlying the effect of APP mutation on Aβ generation is unclear. Therefore, investigating the mechanism of APP mutation on Alzheimer's disease may help understanding of disease pathogenesis. Thus, APP mutations(A673T, A673 V, E682 K, E693 G, and E693Q) were transiently co-transfected into human embryonic kidney cells. Western blot assay was used to detect expression levels of APP, beta-secretase 1, and presenilin 1 in cells. Enzyme-linked immunosorbent assay was performed to determine Aβ_(1–40) and Aβ_(1–42) levels. Liquid chromatography-tandem mass chromatography was used to examine VVIAT, FLF, ITL, VIV, IAT, VIT, TVI, and VVIA peptide levels. Immunofluorescence staining was performed to measure APP and early endosome antigen 1 immunoreactivity. Our results show that the protective A673 T mutation decreases Aβ_(42)/Aβ_(40) rate by downregulating IAT and upregulating VVIA levels. Pathogenic A673 V, E682 K, and E693 Q mutations promote Aβ_(42)/Aβ_(40) rate by increasing levels of CTF99, Aβ_(42), Aβ_(40), and IAT, and decreasing VVIA levels. Pathogenic E693 G mutation shows no significant change in Aβ_(42)/Aβ_(40) ratio because of inhibition of γ-secretase activity. APP mutations can change location from the cell surface to early endosomes. Our findings confirm that certain APP mutations accelerate Aβ generation by affecting the long Aβ cleavage pathway and increasing Aβ_(42/40) rate, thereby resulting in Alzheimer's disease.
基金Supported by:Guangxi Scientific Research and Technological Development Program,No.0630002-2ADoctoral Research and Innovation Program of Guangxi Graduate Education,No, 2007105981007D10
文摘BACKGROUND:During onset and development of Alzheimer's disease,β-amyloid(Aβ) precursor protein(APP),β-site amyloid precursor protein cleaving enzyme(BACE),andβ-amyloid are key genes and proteins in the Aβpathway,and over-expression of these genes can lead to Aβdeposition in the brain. OBJECTIVE:To observe the influence of Longyanshen polysaccharides on expression of BACE, APP,and Aβin the senescence-accelerated mouse prone/8(SAMP8) brain,and to compare these effects with huperzine A treatment. DESIGN,TIME AND SETTING:A randomized,controlled,neurobiochemical experiment was performed at the Department of Pharmacology and Scientific Experimental Center of Guangxi Medical University from September 2005 to January 2008. MATERIALS:Longyanshen polysaccharides powder was extracted from the dried slices of the medicinal plant Longyanshen.The active component,Longyanshen polysaccharides,was provided by the Department of Pharmacology,Guangxi Medical University;huperzine A was purchased from Yuzhong Drug Manufactory,China. METHODS:Healthy SAMP8 mice were used to establish a model of Alzheimer's disease.A total of 50 SAMP8 mice were randomly assigned to 5 groups(n = 10):SAMP8,huperzine A,low-,middle-, and high-dose polysaccharides.In addition,10 senescence-accelerated mouse resistant 1(SAMR1) mice were selected as normal controls.SAMP8 and SAMR1 mice were administered 30 mL/kg normal saline;the huperzine A group was administered 0.02 mg/kg huperzine A;the low-,middle-, and high-dose polysaccharides groups were respectively administered 45,90,and 180 mg/kg Longyanshen polysaccharides.Each group was treated by intragastric administration,once per day, for 50 consecutive days. MAIN OUTCOME MEASURES:One hour after the final administration,immunohistochemical analysis was used to determine Aβexpression in the cortex and hippocampus of SAMP8 mice. Reverse-transcription polymerase chain reaction was used to determine mRNA levels of BACE and APP in SAMP8 brain tissue. RESULTS:Compared with the SAMR1 group,Aβexpression in the cerebral cortex and hippocampus,as well as expression of BACE,APP mRNA in the brain was significantly increased in the SAMP8 group(P<0.05-0.01).Compared with the SAMP8 group,Aβexpression,as well as BACE and APP mRNA expression,were significantly decreased in the cerebral cortex and hippocampus of huperzine A and low-,middle-,and high-dose polysaccharides groups(P<0.05-0.01).In particular,the effect of high-dose polysaccharides was the most significant(P<0.05-0.01). CONCLUSION:Longyanshen polysaccharides reduced or inhibited over-expression of BACE,APP, and Aβin SAMP8 mice in a dose-dependent manner,and the effect was not worse than huperzine A.
文摘Objective To investigate the effects of the total saponin of Dipsacus asperoides (tSDA) and ginsenoside Rb1 (GRb1) on the apoptosis of primary cultured hippocampal neurons induced by β-amyloid protein (Aβ). Methods Primary cultured hippocampal neurons, the cultures were pretreated with tSDA and GRb1 on 10d for 24 hours respectively. Then the cultures were treated with 35 μmol·L -1 Aβ25-35 for 24 hours, observed the changing of survival rate of neurons and the apoptosis of neurons with biochemical analysis combining immunofluorescent cytochemical double-staining technique. Results Hippocampal neurons were treated with 35 μmol·L -1 Aβ for 24 hours, and survival rate of neurons downed to 52.6%. When neurons were pretreated by tSDA and GRb1, survival rate of neurons increased 11% to 15%. The findings of immunofluorescent cytochemical double-staining indicated that apoptotic neurons were obviously more than that of the blank group, reaching 43.9%.When neurons were pretreated by tSDA and GRb1, apoptotic neurons were downed to 16.6%, 10.8% respectively. Conclusion tSDA had the same effects as GRb1, protecting the neurons, antagonizing neurotoxicity of Aβ, increasing survival rate of neurons, and reducing apoptotic neurons induced by Aβ.
基金the National Natural Science Foundation of China,No.30900773the National University Basic Research Foundation of China,No.2010QZZD022
文摘Previous studies have reported that non-human primates and rodents exposed to lead during brain development may become dependent on the deposition of pre-determined β-amyloid protein (Aβ),and exhibit upregulation of β-site amyloid precursor protein expression in old age.However,further evidence is required to elucidate the precise relationship and molecular mechanisms underlying the effects of early lead exposure on excessive Aβ production in adult mammals.The present study investigated the effects of lead exposure on expression of β-amyloid precursor protein cleavage enzyme-1 (BACE-1) in the rat retina and the production of Aβ in early development,using the retina as a window for studying Alzheimer's disease.Adult rats were intraocularly injected with different doses of lead acetate (10μmol/L,100μmol/L,1 mmol/L,10 mmol/L and 100 mmol/L).The results revealed that retinal lead concentration,BACE-1 and its cleavage products β-C-terminal fragment and retina Aβ1-40 were all significantly increased in almost all of the lead exposure groups 48 hours later in a dose-dependent manner.The only exception was the 10μmol/L group.The distribution of BACE-1 in the retina did not exhibit obvious changes,and no distinctive increase in the activation of retinal microglia was apparent.Similarly,retinal synaptophysin expression did not exhibit any clear changes.These data suggest that lead exposure can result in the upregulation of retinal neuron BACE-1 expression in the early period of development and further increase the overproduction of Aβ1-40 in the retina.Our results provided novel insight into the molecular mechanisms underlying environmentally-induced Alzheimer's disease.
基金the Natural Science Foundation of Guangdong Province,No. 031479
文摘BACKGROUND:Modern pharmacological studies have shown that Ginsenoside Rg1 is one of the active components of ginseng that promote intelligence in the nervous system.Ginsenoside Rg1 can improve memory and learning in mouse models ofβ-amyloid protein(Aβ)-induced dementia. OBJECTIVE:To investigate whether effects of Ginsenoside Rg1 against Aβare associated with activity of nuclear factor-kappa B(NF-κB). DESIGN,TIME AND SETTING:The randomized,controlled,cell biological experiment was performed at the DME Center,Institute of Clinical Pharmacology,Guangzhou University of Chinese Medicine,China from July 2005 to May 2006. MATERIALS:Beta-amyloid fragment 25-35(Aβ_(25-35)) was supplied by the Neural Biochemical Laboratory,Xuanwu Hospital,Capital Medical University,China.Ginsenoside Rg1 was obtained from National Institute for the Control of Pharmaceutical and Biological Products,China.Rabbit anti-rat NF-κB p65 antibody was purchased from Santa Cruz Biotechnology,USA. METHODS:Hippocampal neurons and cortical astrocytes of neonatal Sprague Dawley rats were harvested and treated with various concentrations(0,5,10,20,and 40μmol/L) of Aβfor 6,12,and 24 hours to establish cellular models of Alzheimer's disease.Cellular models were pretreated with various concentrations of Ginsenoside Rg1(1,2,4,8,and 16μmol/L).According to cell morphology and activity,the following conditions were selected:40μmol/L Aβfor 24 hours,as well as 2,4,and 8μmol/L Ginsenoside Rg1.NF-κB activity was observed using immunofluorescence and cytochemical staining. MAIN OUTCOME MEASURES:Morphology and viability of hippocampal neurons and cortical astrocytes,and activities of NF-κB were measured. RESULTS:Hippocampal neuron activity was significantly greater in the normal and 2 and 4μmol/L Ginsenoside Rg1 groups compared with the model group(P<0.05).Astrocyte activity was significantly greater in the normal,1,2,4,8,and 16μmol/L Ginsenoside Rg1 groups compared with the model group(P<0.05).NF-κB activity of hippocampal neurons was significantly greater in the normal,2,4,and 8μmol/L Ginsenoside Rg1 groups compared with the model group(P<0.01). NF-κB activity of astrocytes was significantly less in the normal,2,4,and 8μmol/L Ginsenoside Rg1 groups compared with the model group(P<0.01 or P<0.05).No significant difference in NF-κB activity was determined between the 2μmol/L Ginsenoside Rg1 and normal groups(P>0.05). CONCLUSION:Ginsenoside Rg1 protected neural cells by upregulating NF-κB activity in neurons and downregulating NF-κB activity in astrocytes.Ginsenoside Rg1(2μmol/L) maintained cell activity and NF-κB activity at normal levels.
基金supported by the Science and Technology Planning Project of Guangdong Province of China,No.2016A020226022(to HYL)the Medical and Health Technology Project of Guangzhou of China,No.20161A011068(to HYL)the Guangzhou Science Technology and Innovation Commission of China,No.201704020043(to QCG)
文摘Curcumin exerts a neuroprotective effect on Alzheimer’s disease;however,it is not known whether microRNAs are involved in this protective effect.This study was conducted using swAPP695-HEK293 cells as an Alzheimer’s disease cell model.swAPP695-HEK293 cells were treated with 0,0.5,1,2,5,and 10μM curcumin for 24 hours.The changes in miR-15b-5p,miR-19a-3p,miR-195-5p,miR-101-3p,miR-216b-5p,miR-16-5p and miR-185-5p expression were assessed by real-time quantitative polymerase chain reaction.The mRNA and protein levels of amyloid precursor protein,amyloid-β40 and amyloid-β42 were evaluated by quantitative real-time polymerase chain reaction,western blot assays and enzyme-linked immunosorbent assays.swAPP695-HEK293 cells were transfected with miR-15b-5p mimic,or treated with 1μM curcumin 24 hours before miR-15b-5p inhibitor transfection.The effects of curcumin on amyloid precursor protein,amyloid-β40 and amyloid-β42 levels were evaluated by western blot assays and enzyme-linked immunosorbent assay.Luciferase assays were used to analyze the interaction between miR-15b-5p and the 3′-untranslated region of amyloid precursor protein.The results show that amyloid precursor protein and amyloid-βexpression were enhanced in swAPP695-HEK293 cells compared with HEK293 parental cells.Curcumin suppressed the expression of amyloid precursor protein and amyloid-βand up-regulated the expression of miR-15b-5p in swAPP695-HEK293 cells.In addition,we found a negative association of miR-15b-5p expression with amyloid precursor protein and amyloid-βlevels in the curcumin-treated cells.Luciferase assays revealed that miR-15b-5p impaired the luciferase activity of the plasmid harboring the 3′-untranslated region of amyloid precursor protein.These findings indicate that curcumin down-regulates the expression of amyloid precursor protein and amyloid-βin swAPP695-HEK293 cells,which was partially mediated by miR-15b-5p via targeting of the 3′-untranslated region of amyloid precursor protein.
文摘After binding to the estrogen receptor, estrogen can alleviate the toxic effects of beta-amyloid protein, and thereby exert a therapeutic effect on Alzheimer's disease patients. Estrogen can increase the incidence of breast carcinoma and endometrial cancer in post-menopausal women, so it is not suitable for clinical treatment of Alzheimer's disease. There is recent evidence that the estrogen receptor can exert its neuroprotective effects without estrogen dependence. Real-time quantitative PCR and flow cytometry results showed that, compared with non-transfected PC12 cells, adenovirus-mediated estrogen receptor β gene-transfected PC12 cells exhibited lower expression of tumor necrosis factor α and interleukin 1β under stimulation with beta-amyloid protein and stronger protection from apoptosis. The Akt-specific inhibitor Abi-2 decreased the anti-inflammatory and anti-apoptotic effects of estrogen receptor β gene-transfection. These findings suggest that overexpression of estrogen receptor β can alleviate the toxic effect of beta-amyloid protein on PC12 cells, without estrogen dependence. The Akt pathway is one of the potential means for the anti-inflammatory and anti-apoptotic effects of the estrogen receptor.
文摘BACKGROUND: To evaluate and summarize the effects of cerebral perfusion and vascular reserve on the treatment of SICAS. Recently, research on β-amyloid protein has focused on the regulatory effects of es- trogen or phytoestrogen on its deposition. However, there have been only a few reports on dynamic changes of β-amyloid protein deposition in hippocampus of ovariectomized rats. OBJECTIVE: To measureβ-amyloid protein deposition in the hippocampal formation of ovariectomized rats by using immunohistochemistry; to observe time-dependent dynamic changes. DESIGN: Randomized controlled animal study. SETTING: Third Xiangya Hospital of Central South University. MATERIALS: The experiment was carried out in the Central Laboratory of the Third Xiangya Hospital of Central South University from November 2005 to December 2006. Fifty healthy female Sprague Dawley (SD) rats, weighing (293 ± 10) g, were provided by the Animal Laboratory of Xiangya Medical College, Central South University. All rats had neither a childbearing history nor hepatic or renal disease, or skeletal deformity. β-amyloid protein immunohistochemical kit was provided by Wuhan Boster Company. The ex- periment was in accordance with animal ethics standards. METHODS: All rats were randomly divided into five groups, including normal control group (n = 10), sham operation group (n = 10), and ovariectomized group (n = 30). After anesthesia in the ovariectomized group, the bilateral ovaries were separated and resected. The same volume of fat was resected in the sham operation group. Rats from the normal control group, however, did not receive any surgical treatments. Rats in the normal control group and sham operation group were sacrificed by anesthesia 7 weeks after surgery. Every ten rats from the ovariectomized group was respectively sacrificed at 7, 15, and 30 weeks after surgery. Immunohistochemistry was used to detectβ-amyloid protein deposition in hippocampal sections. Cell counting and gray value measurements served to record the dynamic changes in β-amyloid protein deposi- tion. MAIN OUTCOME MEASURES: ① Morphological changes. ② Positive cell counts from β-amyloid protein stainings and gray value measurements. RESULTS: All 50 rats were involved in the final analysis. ① Morphological changes. β-amyloid-positive cells were detected in the hippocampus of all rats. Biebrich scarlet stained neurites with a swollen cytoplasm. A few β-amyloid-positive cells were observed in all groups 7 weeks after surgery, and plasma and neurites were slightly stained. By 15 weeks after surgery, a number of β-amyloid-positive cells were observed in the ovariectomized group, and plasma and neurites were also slightly stained. By 30 weeks after surgery, how- ever, many β-amyloid-positive cells were observed in the ovariectomized group. These cells were partially aggregated and darkly stained. ② Positive cell counts and gray value of β-amyloid protein in hippocam- pus. At 7 weeks after surgery, cell counts and gray value measurements were not significantly different in the ovariectomized group compared to the sham operation group and normal control group (P > 0.05). Cell counts and gray value measurements were higher in the ovariectomized group by 15 weeks compared to those by 7 weeks in the normal control group, sham operation group and ovariectomized group (P < 0.05). At 30 weeks after surgery, cell counts and gray value measurements were higher in the ovariectomized group compared to the normal control group. In addition, there were significant differences between sham opera- tion group and ovariectomized group at 7 and 15 weeks after operation (P < 0.05-0.01). Cell counts and gray value measurements increased in all groups over time. CONCLUSION: Extended estrogen deficiency in rats can increase β-amyloid protein deposition in the hippocampus and the deposition increases over time.
文摘Objective To explore the effect of β-amyloid protein (Aβ) on S100β expression in rat hippocampus and its mechanisms. Methods At 7 days after bilateral stereotaxis injection of different dose of fibrillar Aβ 25-35 and interluekin-1 receptor antagonist (IL-1ra) into the rat CA1 region, the learning and memory abilities of rats were tested with passive avoidance task. Amyloid deposition was detected by using Congo red staining technique. Nissl staining and immunohistochemical techniques were used to analyze the number of neurons, and GFAP and the S100β expression in hippocampal CA1 region , respectively. Results After fibrillar Aβ injection, the step-through latency of rats was significantly shortened compared to that of the control group. The GFAP positive astrocytes were found surrounding amyloid deposition. Neuronal loss occurred in the pyramidal cell layer of CA1 region. The number of S100β positive cells in Aβ-treated group was significantly increased compared with that in the control group. After IL-1ra injection, the number of S100β positive cells was significantly decreased. Conclusion Intrahippocampal injection of Aβ 25-35 could cause similar pathologic changes of Alzheimer's disease. Aβ 25-35 was capable of up-regulating S100β expression in a dose-dependent manner. The injection of IL-1ra could attenuate the effect of Aβ on S100β expression.
文摘Aim: The abnormal accumulation, assembly and deposition of the amyloid β-protein (Aβ) are prominent pathological features of patients with Alzheimer’s disease (AD) and related disorders. A number of factors in the brain can influence Aβ accumulation and associated pathologies. The aim of the present study was to determine the consequences of deleting nitric oxide synthase (NOS) 3, the endothelial form of NOS, in Tg-5xFAD mice, a model of parenchymal AD-like amyloid pathology. Methods: Tg-5xFAD mice were bred with NOS3-/- mice. Cohorts of Tg-5xFAD mice and bigenic Tg-5xFAD/NOS3-/- mice were aged to six months followed by collection of the blood and brain tissues from the mice for biochemical and pathological analyses. Results: ELISA analyses show that the absence of NOS3 results in elevated levels of cerebral and plasma Aβ peptides in Tg-5xFAD mice. Immunohistochemical analyses show that the absence of NOS3 increased the amount of parenchymal Aβ deposition and fibrillar amyloid accumulation in Tg-5xFAD mice. The elevated levels of Aβ were not due to changes in the expression levels of transgene encoded human amyloid precursor protein (APP), endogenous β-secretase, or increased proteolytic processing of APP. Conclusions: The results from this study suggest that the loss of NOS3 activity enhances Aβ pathology in Tg-5xFAD mice. These findings are similar to previous studies of NOS2 deletion suggesting that reduced NOS activity and NO levels enhance amyloid-associated pathologies in human APP transgenic mice.
基金supported by the National Natural Science Foundation of China,No.81070873,30970932Ningbo Natural Science Foundation,No.2011A610065,2010A610072,2011A610064,2011C51006the Scientific Research Fund of Zhejiang Provincial Education Department,No.Y201018164
文摘Previous studies indicate that memantine, a low-affinity N-methyl-D-aspartate receptor antagonist, exerted acute protective effects against amyloid-β protein-induced neurotoxicity. In the present study, the chronic effects and mechanisms of memantine were investigated further using electrophysiological methods. The results showed that 7-day intraperitoneal application of memantine, at doses of 5 mg/kg or 20 mg/kg, did not alter hippocampal long-term potentiation induction in rats, while 40 mg/kg memantine presented potent long-term potentiation inhibition. Then further in vitro studys were carried out in 5 mg/kg and 20 mg/kg memantine treated rats. We found that 20 mg/kg memantine attenuated the potent long-term potentiation inhibition caused by exposure to amyloid-β protein in the dentate gyrus in vitro. These findings are the first to demonstrate the antagonizing effect of long-term systematic treatment of memantine against amyloid-β protein triggered long-term potentiation inhibition to improve synaptic plasticity.
基金the National Natural Science Foundation of China,No. NSFC-3027164
文摘BACKGROUND:Previous studies have demonstrated that Piper futokadsura stem selectively inhibits expression of amyloid precursor protein(APP) at the mRNA level.In addition,the piperlonguminine(A) and dihydropiperlonguminine(B) components(1:0.8),which can be separated from Futokadsura stem,selectively inhibit expression of the APP at mRNA and protein levels. OBJECTIVE:Based on previous findings,the present study investigated the effects ofβ-site amyloid precursor protein cleaving enzyme(BACE1) and APP genes on the production ofβ-amyloid peptide 42(Aβ42) in human neuroblastoma cells(SK-N-SH cells) using small interfering RNAs (siRNAs) and A/B components separated from Futokadsura stem,respectively. DESIGN,TIME AND SETTING:A gene interference-based randomized,controlled,in vitro experiment was performed at the Key Laboratory of Cardiovascular Remodeling and Function Research,Ministries of Education and Public Health,and Institute of Pharmacologic Research, School of Pharmaceutical Science & Department of Biochemistry,School of Medicine,Shandong University between July 2006 and December 2007. MATERIALS:SK-N-SH cells were provided by Shanghai Institutes of Biological Sciences,Chinese Academy of Sciences,Shanghai,China;mouse anti-human BACE1 monoclonal antibody was purchased from R&D Systems,USA;mouse anti-human APP monoclonal antibody was purchased from Cell Signaling Technology,USA;and horseradish peroxidase(HRP)-conjugated goat anti-mouse IgG was provided by Sigma,USA. METHODS:The human BACE1 cDNA sequence was obtained from NCBI website (www.ncbi.nlm.nih.gov/sites/entrez).Three pairs of siRNAs,specific to human BACE1 gene,were synthesized through the use of Silencer^(?) pre-designed siRNA specification,and were transfected into SK-N-SH cells with siPORT NeoFX transfection agent to compare the effects of different concentrations of siRNAs(10-50 nmol/L) on SK-N-SH cells.Futokadsura stem was separated and purified with chemical methods,and the crystal was composed of A/B components,with an A to B ratio of 1:0.8.The A/B(1:0.8) components were added to the SK-N-SH cells at different concentrations(13.13,6.56,and 3.28 mg/mL). MAIN OUTCOME MEASURES:Using RT-PCR and Western blot methods,BACE1 and APP expression at mRNA and protein levels was detected in SK-N-SH cells following treatment with different siRNAs and concentrations of Futokadsura stem-separated A/B components,respectively. Altered Aβ42 secretion by SK-N-SH cells was determined by ELISA. RESULTS:BACE1 mRNA and protein levels were significantly suppressed by 40 and 50 nmol/L siRNAs at 48 hours post-transfection.A/B components(1:0.8),which were separated from Futokadsura stem,selectively inhibited mRNA and protein expression of APP in SK-N-SH cells. Aβ42 secretion by SK-N-SH cells was significantly decreased following treatment with siRNAs or A/B components. CONCLUSION:Inhibition of BACE1 and APP genes by various materials and methods efficiently decreased production of Aβ42.
基金Supported by: the National Natural Science Foundation of China, No. 30770737
文摘BACKGROUND: Studies have shown that scorpion venom heat-resistant protein (SVHRP) exhibitsprotective effects on primary cultured hippocampal neurons.OBJECTIVE: To determine the effects of SVHRP on astrocyte activity and synaptic density in thehippocampus induced by amyloid β peptide 1-40 (Aβ_(1-40)) neurotoxicity.DESIGN, TIME AND SETTING: The randomized, controlled, animal experiment was performed atthe Central Laboratory, the Laboratory of Human Anatomy, and the Laboratory of Physiology, inDalian Medical University between March 2006 and June 2008.MATERIALS: Aβ_(1-40) was provided by Biosource, USA; SVHRP was a patented biological product ofDalian Medical University (No. ZL01 1 06166.9).METHODS: A total of 27 healthy, 2-month-old, male SD rats were randomly assigned to 3 groups:control, Aβ, and SVHRP, with 9 rats in each group. Alzheimer's disease was simulated with 10 μgAβ_(1-40) bilaterally injected into the hippocampus of the Aβ and SVHRP groups. The control group wasinjected with 2 μL 0.05% trifluoroacetic acid. One day following model establishment, the SVHRPgroup received an intraperitoneal injection of 2 μg/100 g SVHRP, while the control group and Aβgroup received 0.5 mL/100 g tri-distilled water, once per day, for 10 consecutive days.MAIN OUTCOME MEASURES: At 16 days following model establishment, synaptophysin (p38)expression in CA1 CA4 regions of the rat hippocampus was determined by immunohistochemistry.Glial fibrillary acidic protein (GFAP) expression surrounding the hippocampal Aβ_(1-40) injected areawas also detected. At 11 days following model establishment, escape latency, swimming time, anddistance to target quadrant were measured using the Morris water maze.RESULTS: Compared with the control group, the Aβ group exhibited notably reduced p38expression (P < 0.05) and notably increased GFAP expression in the rat hippocampus (P < 0.05).Water maze results demonstrated that escape latency was prolonged (P < 0.05), and swimming timeand distance to the target quadrant were shortened in the Aβ group. Compared with the Aβ group,the SVHRP group exhibited notably increased p38 expression (P < 0.05) and notably decreasedGFAP expression in the rat hippocampus (P < 0.05). Water maze results demonstrated that escapelatency was significantly reduced (P < 0.05), and swimming time and distance to the target quadrantwere significantly prolonged.CONCLUSION: SVHRP inhibited exogenous Aβ_(1-40)-induced astrocyte activation and synapticdensity decline in the rat hippocampus. Place navigation and spatial searching results showed thatSVHRP blocked Aβ_(1-40)-induced impaired learning and memory.
基金the NatureScience Foundation of Jiangsu Province, No.BK2005002the International Cooperation Program and talented manprogram of Jiangsu Provinceof China, No. BZ2006045,06-B-002
文摘BACKGROUND: Tongxinluo has been clinically proven to be effective in improving memory and cognitive function in patients with post-stroke vascular dementia. Is the mechanism related to the deposition of beta-amyloid peptide (Aβ) in hippocampus? OBJECTIVE: To observe the effect of Tongxinluo on cognitive impairment in a mouse model with vascular dementia and the changes of Aβ deposition andβ-secretase 1 (BACE1) expression. DESIGN: Randomized controlled study. SETTING: State Key Laboratory of Pharmaceutical Biotechnology of Nanjing University and Affiliated Drum Tower Hospital of Nanjing University Medical School. MATERIALS: The experiment was carried out in the State Key Laboratory of Pharmaceutical Biotechnology of Nanjing University and Affiliated Drum Tower Hospital of Nanjing University Medical School from March 2006 to January 2007. A total of 36 healthy Kunming mice, 18 of each gender, were chosen. The study was conducted in accordance with the National Regulations of Experimental Animal Administration, and all animal experiments were approved by the Committee of Experimental Animal Administration of Nanjing University. Tongxinluo was provided by Shijiazhuang Yiling Pharmaceutical Co., Ltd. METHODS: All mice were randomly divided into 6 groups, including naive control (n=6), sham-operated control (n=6) and experimental groups treated with different doses of Tongxinluo (0.2, 0.4, and 0.6 g/kg/d; n=6 for each group) or vehicle (n=6). Five groups were subjected to bilateral common carotid arteries (2-VO) occlusion to produce a vascular dementia model (no occlusion was performed in sham-operated group). The mice in the Tongxinluo treatment groups were intragastricly administered daily with a Tongxinluo suspension (40 g/L in distilled water) at doses of 0.2, 0.4 or 0.6 g/kg/d from day 1 to day 30 post-surgery. The animals in vehicle, sham-operated and naive groups were administered an equal volume of distilled water. MAIN OUTCOME MEASURES: ①Escape latency time determined in all groups of mice before and after 2-VO occlusion by Morris water maze. ②Changes in BACE1 mRNA expression in the hippocampi of mice among the six groups by RT-PCR assay, and BACE1 and Aβ protein expression in the hippocampi of mice by Western blot. RESULTS: All 36 mice were involved in the final analysis. ① No difference was detected in escape latency time to a hidden platform among all groups in water maze test before surgery (P > 0.05) At 30 days after 2-VO occlusion, the vehicle animals exhibited a significantly longer latency in finding the hidden platform compared to that of sham-operated and naive animals (P < 0.01). The prolonged escape latency was significantly reduced by oral administration of 0.4 g or 0.6 kg/day (P < 0.01, P < 0.05). BACE1 mRNA and protein expression in vehicle animals were much higher than in sham-operated and naive animals (P < 0.01). The ischemia-induced increases in BACE1 mRNA and protein level were attenuated by all three doses of Tongxinluo treatment (P < 0.01), and the 0.4 g/kg/d treatment was the most effective. Aβ protein expression in vehicle animals after 2-VO occlusion were much higher than in sham-operated and na?ve animals (P < 0.01). 2-VO occlusion-induced Aβ generation was significantly attenuated by all doses of Tongxinluo treatment, with the most effective dose being 0.4 g/kg/d (P < 0.01). CONCLUSION: BACE1 mRNA levels and protein levels of BACE1 and Aβare reduced in the hippocampi of vascular dementia model mice by all three doses of Tongxinluo treatment, with the most effective dose being 0.4 g/kg/d. The results suggest that inhibition of post-ischemia BACE1 expression and Aβ generation in brain might underlie Tongxinluo’s effects in improving cognitive impairment.
