BACKGROUND:Studies have demonstrated that the mechanisms underlying cellular apoptosis signal transduction focus on two pathways:intracellular mitochondria and extracellular death receptor.The current evidence support...BACKGROUND:Studies have demonstrated that the mechanisms underlying cellular apoptosis signal transduction focus on two pathways:intracellular mitochondria and extracellular death receptor.The current evidence supports that signal transduction of cellular apoptosis also includes endoplasmic reticulum stress signal transduction. OBJECTIVE:To observe Caspase-12 expression and cellular apoptosis following ischemia in rats with progressive spinal cord compression,and to verify the influence of endoplasmic reticulum stress on the apoptosis induced by spinal cord injury. DESIGN,TIME AND SETTING:A randomized,controlled,animal trial was performed at the Institute of Neuroscience in Chongqing Medical University between January and October in 2006. MATERIALS:Immunohistochemical kit,diaminobenzidine,and TUNEL kit were purchased from Beijing Zhongshan Biotechnology,China;rabbit anti-rat Caspase-12 monoclonal antibody was provided by Santa Cruz,USA. METHODS:Sixty Wistar rats,aged 3-4 months,were randomly assigned to a model group(n=50), which underwent spinal cord compression in the L_1 segment following L_1 laminectomy and articular process excision to establish a model of progressive spinal cord compression,and a sham-surgery group(n=10),which underwent only laminectomy.Starting with the first day after surgery,the rats were locally anesthetized,the skin was opened,and the screw was rotated by 1/4 of a cycle,twice weekly. MAIN OUTCOME MEASURES:At 3,7,14,21,and 28 days after surgery,rats from each group were anesthetized,and the spinal cords were resected.Pathological changes following spinal cord compression were determined using hematoxylin-eosin staining,Nissl dye,and transmission electron microscopy.The TUNEL method was used to observe neuronal apoptosis in the compressed spinal cord segments.Immunohistochemistry and Western blot were utilized to detect Caspase-12 expression in the compressed segments. RESULTS:Cellular swelling,neural degeneration,and altered endoplasmic reticulum structures were observed at 3 days following compression.Symptoms became gradually aggravated with increasing compression time.Compared with the sham-surgery group,the number of apoptotic neurons was remarkably increased in compressed segments of the model group(P<0.05),and Caspase-12 expression was also shown to increase(P<0.05). CONCLUSION:Neuronal apoptosis was a predominant pathological factor resulting in secondary spinal cord injury during progressive spinal cord compression,and Caspase-12 was shown to be possibly involved in neuronal apoptosis induced by progressive spinal cord compression.展开更多
BACKGROUND: Aquaporin-4 (AQP4) is abundant in astrocytes, ependymal cells, and the choroid plexus, and is associated with cerebrospinal fluid formation and osmoregulation. AQP4 is speculated to be the hypothalamic osm...BACKGROUND: Aquaporin-4 (AQP4) is abundant in astrocytes, ependymal cells, and the choroid plexus, and is associated with cerebrospinal fluid formation and osmoregulation. AQP4 is speculated to be the hypothalamic osmoreceptor and regulator of water balance. OBJECTIVE: To examine AQP4 expression and its role in cultured rat astrocytes after exposure to hypotonic medium. DESIGN, TIME AND SETTING: Randomized control experiment. This experiment was carried out in the Research Room of Neurobiology, Chongqing University of Medical Science, China, between April and October 2003. MATERIALS: Two-day-old newborn Wistar rats (n =20), weighing 10-15 g, were purchased from the Experimental Animal Center of Chongqing University of Medical Science, China. METHODS: Purified rat cerebral cortical astrocytes were isolated from Wistar rats for in vitro cell culture experiments. The cells were randomly divided into control and hypotonic groups. The in vitro cell edema model was established by exposing astrocytes to hypotonic medium (268, 254, or 240 mmol/L). Cells in the control group were cultured in normal culture medium. MAIN OUTCOME MEASURES: Morphological changes in astrocytes were observed under an inverted microscope and a transmission electron microscope after cells were cultured for 3, 6, 12, or 24 hours with hypotonic medium or normal culture medium. In each group, AQP4 protein and mRNA expression were assessed by immunocytochemistry, in situ hybridization, and reverse transcription polymerase chain reaction at the different time points. RESULTS: After astrocytes were cultured for 3, 6, 12, or 24 hours with hypotonic medium (268, 254, 240 mmol/L), they showed typical features of cell edema. In the control group, no astrocytes developed pathological changes. There were no significant changes in the AQP4 mRNA and protein expression in the control group at any of the time points after astrocytes were cultured with normal culture medium (P > 0.05). Compared with the control group, AQP4 mRNA and protein expression in the hypotonic group were remarkably increased at all time points after astrocytes cultured with hypotonic medium (268, 254, 240 mmol/L; P < 0.05). AQP4 mRNA and protein expression increased with increasing exposure time and with decreasing concentration of the hypotonic medium. CONCLUSION: Hypotonic medium induced cell edema and increased AQP4 mRNA and protein expression. Up-regulated expression of AQP4 was correlated with hypotonic medium concentration in a time dependent manner.展开更多
BACKGROUND:Tyrosine hydroxylase and phenylethanolamine-n-methyl transferase expression coexist in Purkinje cells of the rat cerebellum.Numerous reports have also been published addressing whether dopamine-beta-hydroxy...BACKGROUND:Tyrosine hydroxylase and phenylethanolamine-n-methyl transferase expression coexist in Purkinje cells of the rat cerebellum.Numerous reports have also been published addressing whether dopamine-beta-hydroxylase(DBH) expression exists in cerebellar Purkinje cells. OBJECTIVE:To investigate the coexistence of DBH and activator protein-2αexpression in rat cerebellar Purkinje cells. DESIGN,TIME AND SETTING:A cell morphological study was performed at the Institute of Neuroscience,Chongqing Medical University,China in May 2007. MATERIALS:Ten healthy Wistar rats,of either gender,aged 14 weeks,served as experimental animals.Rabbit anti-mouse DBH,goat anti-mouse activator protein-2αand rabbit anti-mouseβ-actin (Santa Cruz Biotechnology,Inc.,USA),horseradish peroxidase-labeled goat anti-rabbit IgG, FITC-labeled mouse anti-rabbit IgG,and Cy3-labeled mouse anti-goat IgG(Boster,Wuhan,China), were used in this study. METHODS:Immunohistochemical staining was used to measure the expression of DBH or activator protein-2α,with double-label immunofluorescence being employed to determine coexpression of both,in the cerebellum of 5 randomly selected rats.Western blot assay was utilized to determine the expression of DBH and activator protein-2αin the cerebellum of the remaining 5 rats. MAIN OUTCOME MEASURES:Expression,localization and coexistence of DBH and activator protein-2αin the cerebellum were measured separately. RESULTS:Immunohistochemical staining demonstrated that cerebellar Purkinje cells stained positive for DBH and activator protein-2α.Western blot assay also demonstrated DBH and activator protein-2αexpression in the cerebellum.Double-labeling immunofluorescence showed the coexistence of DBH and activator protein-2αin cerebellar Purkinje cells. CONCLUSION:Norepinephrine and activator protein-2αcoexist in rat cerebellar Purkinje cells.展开更多
基金the National Natural Science Foundation of China,No.30270437Chunhui Program of the Ministry of Education in 2003, No.200407
文摘BACKGROUND:Studies have demonstrated that the mechanisms underlying cellular apoptosis signal transduction focus on two pathways:intracellular mitochondria and extracellular death receptor.The current evidence supports that signal transduction of cellular apoptosis also includes endoplasmic reticulum stress signal transduction. OBJECTIVE:To observe Caspase-12 expression and cellular apoptosis following ischemia in rats with progressive spinal cord compression,and to verify the influence of endoplasmic reticulum stress on the apoptosis induced by spinal cord injury. DESIGN,TIME AND SETTING:A randomized,controlled,animal trial was performed at the Institute of Neuroscience in Chongqing Medical University between January and October in 2006. MATERIALS:Immunohistochemical kit,diaminobenzidine,and TUNEL kit were purchased from Beijing Zhongshan Biotechnology,China;rabbit anti-rat Caspase-12 monoclonal antibody was provided by Santa Cruz,USA. METHODS:Sixty Wistar rats,aged 3-4 months,were randomly assigned to a model group(n=50), which underwent spinal cord compression in the L_1 segment following L_1 laminectomy and articular process excision to establish a model of progressive spinal cord compression,and a sham-surgery group(n=10),which underwent only laminectomy.Starting with the first day after surgery,the rats were locally anesthetized,the skin was opened,and the screw was rotated by 1/4 of a cycle,twice weekly. MAIN OUTCOME MEASURES:At 3,7,14,21,and 28 days after surgery,rats from each group were anesthetized,and the spinal cords were resected.Pathological changes following spinal cord compression were determined using hematoxylin-eosin staining,Nissl dye,and transmission electron microscopy.The TUNEL method was used to observe neuronal apoptosis in the compressed spinal cord segments.Immunohistochemistry and Western blot were utilized to detect Caspase-12 expression in the compressed segments. RESULTS:Cellular swelling,neural degeneration,and altered endoplasmic reticulum structures were observed at 3 days following compression.Symptoms became gradually aggravated with increasing compression time.Compared with the sham-surgery group,the number of apoptotic neurons was remarkably increased in compressed segments of the model group(P<0.05),and Caspase-12 expression was also shown to increase(P<0.05). CONCLUSION:Neuronal apoptosis was a predominant pathological factor resulting in secondary spinal cord injury during progressive spinal cord compression,and Caspase-12 was shown to be possibly involved in neuronal apoptosis induced by progressive spinal cord compression.
基金the National Natural Science Foundation of China, No.30070247
文摘BACKGROUND: Aquaporin-4 (AQP4) is abundant in astrocytes, ependymal cells, and the choroid plexus, and is associated with cerebrospinal fluid formation and osmoregulation. AQP4 is speculated to be the hypothalamic osmoreceptor and regulator of water balance. OBJECTIVE: To examine AQP4 expression and its role in cultured rat astrocytes after exposure to hypotonic medium. DESIGN, TIME AND SETTING: Randomized control experiment. This experiment was carried out in the Research Room of Neurobiology, Chongqing University of Medical Science, China, between April and October 2003. MATERIALS: Two-day-old newborn Wistar rats (n =20), weighing 10-15 g, were purchased from the Experimental Animal Center of Chongqing University of Medical Science, China. METHODS: Purified rat cerebral cortical astrocytes were isolated from Wistar rats for in vitro cell culture experiments. The cells were randomly divided into control and hypotonic groups. The in vitro cell edema model was established by exposing astrocytes to hypotonic medium (268, 254, or 240 mmol/L). Cells in the control group were cultured in normal culture medium. MAIN OUTCOME MEASURES: Morphological changes in astrocytes were observed under an inverted microscope and a transmission electron microscope after cells were cultured for 3, 6, 12, or 24 hours with hypotonic medium or normal culture medium. In each group, AQP4 protein and mRNA expression were assessed by immunocytochemistry, in situ hybridization, and reverse transcription polymerase chain reaction at the different time points. RESULTS: After astrocytes were cultured for 3, 6, 12, or 24 hours with hypotonic medium (268, 254, 240 mmol/L), they showed typical features of cell edema. In the control group, no astrocytes developed pathological changes. There were no significant changes in the AQP4 mRNA and protein expression in the control group at any of the time points after astrocytes were cultured with normal culture medium (P > 0.05). Compared with the control group, AQP4 mRNA and protein expression in the hypotonic group were remarkably increased at all time points after astrocytes cultured with hypotonic medium (268, 254, 240 mmol/L; P < 0.05). AQP4 mRNA and protein expression increased with increasing exposure time and with decreasing concentration of the hypotonic medium. CONCLUSION: Hypotonic medium induced cell edema and increased AQP4 mRNA and protein expression. Up-regulated expression of AQP4 was correlated with hypotonic medium concentration in a time dependent manner.
基金the National Natural Science Foundation of China.No.30270437
文摘BACKGROUND:Tyrosine hydroxylase and phenylethanolamine-n-methyl transferase expression coexist in Purkinje cells of the rat cerebellum.Numerous reports have also been published addressing whether dopamine-beta-hydroxylase(DBH) expression exists in cerebellar Purkinje cells. OBJECTIVE:To investigate the coexistence of DBH and activator protein-2αexpression in rat cerebellar Purkinje cells. DESIGN,TIME AND SETTING:A cell morphological study was performed at the Institute of Neuroscience,Chongqing Medical University,China in May 2007. MATERIALS:Ten healthy Wistar rats,of either gender,aged 14 weeks,served as experimental animals.Rabbit anti-mouse DBH,goat anti-mouse activator protein-2αand rabbit anti-mouseβ-actin (Santa Cruz Biotechnology,Inc.,USA),horseradish peroxidase-labeled goat anti-rabbit IgG, FITC-labeled mouse anti-rabbit IgG,and Cy3-labeled mouse anti-goat IgG(Boster,Wuhan,China), were used in this study. METHODS:Immunohistochemical staining was used to measure the expression of DBH or activator protein-2α,with double-label immunofluorescence being employed to determine coexpression of both,in the cerebellum of 5 randomly selected rats.Western blot assay was utilized to determine the expression of DBH and activator protein-2αin the cerebellum of the remaining 5 rats. MAIN OUTCOME MEASURES:Expression,localization and coexistence of DBH and activator protein-2αin the cerebellum were measured separately. RESULTS:Immunohistochemical staining demonstrated that cerebellar Purkinje cells stained positive for DBH and activator protein-2α.Western blot assay also demonstrated DBH and activator protein-2αexpression in the cerebellum.Double-labeling immunofluorescence showed the coexistence of DBH and activator protein-2αin cerebellar Purkinje cells. CONCLUSION:Norepinephrine and activator protein-2αcoexist in rat cerebellar Purkinje cells.
