Objective: To characterize the expression of aquaporin-4 (AQP4), one of the aquaporins (AQPs), in human brain specimens from patients with traumatic brain injury or brain tumors. Methods: Nineteen human brain specimen...Objective: To characterize the expression of aquaporin-4 (AQP4), one of the aquaporins (AQPs), in human brain specimens from patients with traumatic brain injury or brain tumors. Methods: Nineteen human brain specimens were obtained from the patients with traumatic brain injury, brain tumors, benign meningioma or early stage hemorrhagic stroke. MRI or CT imaging was used to assess brain edema. Hematoxylin and eosin staining were used to evaluate cell damage. Immunohistochemistry was used to detect the AQP4 expression. Results: AQP4 expression was increased from 15h to at least 8 d after injury. AQP4immunoreactivity was strong around astrocytomas, ganglioglioma and metastatic adenocarcinoma. However, AQP4 immunoreactivity was only found in the centers of astrocytomas and ganglioglioma, but not in metastatic adenocarcinoma derived from lung.Conclusion: AQP4 expression increases in human brains after traumatic brain injury, within brain-derived tumors, and around brain tumors.展开更多
Objective To investigate the role of extracellular signal-regulated kinase1/2(ERK1/2) pathway in the regulation of aquaporin 4(AQP4) expression in cultured astrocytes after scratch-injury. Methods The scratch-injury m...Objective To investigate the role of extracellular signal-regulated kinase1/2(ERK1/2) pathway in the regulation of aquaporin 4(AQP4) expression in cultured astrocytes after scratch-injury. Methods The scratch-injury model was produced in cultured astrocytes of rat by a 10-μL plastic pipette tip. The morphological changes of astrocytes and lactate dehydrogenase(LDH) leakages were observed to assess the degree of scratch-injury. AQP4 expression was detected by immunofluorescence staining and Western blot, and phosphorylated-ERK1/2(p-ERK1/2) expression was determined by Western blot. To explore the effect of ERK1/2 pathway on AQP4 expression in scratch-injured astrocytes, 10 μmol/L U0126(ERK1/2 inhibitor) was incubated in the medium at 30 min before the scratch-injury in some groups. Results Increases in LDH leakage were observed at 1, 12, and 24 h after scratch-injury, and AQP4 expression was reduced simultaneously. Decrease in AQP4 expression was associated with a significant increase in ERK1/2 activation. Furthermore, pretreatment with U0126 blocked both ERK1/2 activation and decrease in AQP4 expression induced by scratch-injury. Conclusion These results indicate that ERK1/2 pathway down-regulates AQP4 expression in scratch-injured astrocytes, and ERK1/2 pathway might be a novel therapeutic target in reversing the effects of astrocytes that contribute to traumatic brain edema.展开更多
To investigate the effects of mRNA interference on aquaporin-4 expression in swollen tissue of rats with ischemic cerebral edema, and diagnose the significance of diffusion-weighted MRI, we injected 5 μL shRNA- aquap...To investigate the effects of mRNA interference on aquaporin-4 expression in swollen tissue of rats with ischemic cerebral edema, and diagnose the significance of diffusion-weighted MRI, we injected 5 μL shRNA- aquaporin-4 (control group) or siRNA- aquaporin-4 solution (1:800) (RNA interference group) into the rat right basal ganglia immediately before occlusion of the middle cerebral artery. At 0.25 hours after occlusion of the middle cerebral artery, diffusion-weighted MRI displayed a high signal; within 2 hours, the relative apparent diffusion coefficient decreased markedly, aquaporin-4 expression increased rapidly, and intracellular edema was obviously aggravated; at 4 and 6 hours, the relative apparent diffusion coefficient slowly returned to control levels, aquaporin-4 expression slightly increased, and angioedema was observed. In the RNA interference group, during 0.25- 6 hours after injection of siRNA- aquaporin-4 solution, the relative apparent diffusion coefficient slightly fluctuated and aquaporin-4 expression was upregulated; during 0.5-4 hours, the relative apparent diffusion coefficient was significantly higher, while aquaporin-4 expression was significantly lower when compared with the control group, and intracellular edema was markedly reduced; at 0.25 and 6 hours, the relative apparent diffusion coefficient and aquaporin-4 expression were similar when compared with the control group; obvious angioedema remained at 6 hours. Pearson's correlation test results showed that aquaporin-4 expression was negatively correlated with the apparent diffusion coefficient (r = -0.806, P < 0.01). These findings suggest that upregulated aquaporin-4 expression is likely to be the main molecular mechanism of intracellular edema and may be the molecular basis for decreased relative apparent diffusion coefficient. Aquaporin-4 gene interference can effectively inhibit the upregulation of aquaporin-4 expression during the stage of intracellular edema with time-effectiveness. Moreover, diffusion-weighted MRI can accurately detect intracellular edema.展开更多
In the present study, rabbits were treated with hyperbaric oxygen for 1 hour after detonator-blast-induced craniocerebral injury. Immunohistochemistry showed significantly reduced aquaporin 4 expression and adrenocort...In the present study, rabbits were treated with hyperbaric oxygen for 1 hour after detonator-blast-induced craniocerebral injury. Immunohistochemistry showed significantly reduced aquaporin 4 expression and adrenocorticotropic hormone expression in the pituitary gland of rabbits with craniocerebral injury. Aquaporin 4 expression was positively correlated with adrenocorticotropic hormone expression. These findings indicate that early hyperbaric oxygen therapy may suppress adrenocorticotropic hormone secretion by inhibiting aquaporin 4 expression.展开更多
Aquaporin-4 regulates water molecule channels and is important in tissue regulation and water transportation in the brain. Upregulation of aquaporin-4 expression is closely related to cellular edema after early cerebr...Aquaporin-4 regulates water molecule channels and is important in tissue regulation and water transportation in the brain. Upregulation of aquaporin-4 expression is closely related to cellular edema after early cerebral infarction. Cellular edema and aquaporin-4 expression can be determined by measuring cerebral infarct area and apparent diffusion coefficient using diffusion-weighted imaging(DWI). We examined the effects of silencing aquaporin-4 on cerebral infarction. Rat models of cerebral infarction were established by occlusion of the right middle cerebral artery and si RNA-aquaporin-4 was immediately injected via the right basal ganglia. In control animals, the area of high signal intensity and relative apparent diffusion coefficient value on T2-weighted imaging(T2WI) and DWI gradually increased within 0.5–6 hours after cerebral infarction. After aquaporin-4 gene silencing, the area of high signal intensity on T2 WI and DWI reduced, relative apparent diffusion coefficient value was increased, and cellular edema was obviously alleviated. At 6 hours after cerebral infarction, the apparent diffusion coefficient value was similar between treatment and model groups, but angioedema was still obvious in the treatment group. These results indicate that aquaporin-4 gene silencing can effectively relieve cellular edema after early cerebral infarction; and when conducted accurately and on time, the diffusion coefficient value and the area of high signal intensity on T2 WI and DWI can reflect therapeutic effects of aquaporin-4 gene silencing on cellular edema.展开更多
Ammonia induces astrocyte swelling, which is strongly associated with overexpression of aquaporin-4. However, the mechanisms by which ammonia induces astrocyte swelling, and subsequently upregulating aquaporin-4 expre...Ammonia induces astrocyte swelling, which is strongly associated with overexpression of aquaporin-4. However, the mechanisms by which ammonia induces astrocyte swelling, and subsequently upregulating aquaporin-4 expression, remain unknown. In the present study, astrocytes were cultured in vitro and exposed to ammonium chloride (NH4Cl), followed by propofol, protein kinase C agonist, or antagonist, respectively. Astrocyte morphology was observed by light microscopy, and aquaporin-4 expression was detected by western blot analysis. Results showed that propofol or protein kinase C agonist significantly attenuated the degree of NH4Cl-induced astrocyte swelling and inhibited increased aquaporin-4 expression. Propofol treatment inhibited aquaporin-4 overexpression in cultured astrocyte induced by NH4Cl; protein kinase C pathway activation is potentially involved.展开更多
BACKGROUND:Aquaporin-4 (AQP-4) over-expression following cerebral ischemia results in cerebral edema. Picroside Ⅱ has been shown to exhibit a neuroprotective effect on neuronal apoptosis. However,few reports have add...BACKGROUND:Aquaporin-4 (AQP-4) over-expression following cerebral ischemia results in cerebral edema. Picroside Ⅱ has been shown to exhibit a neuroprotective effect on neuronal apoptosis. However,few reports have addressed the neuroprotective mechanisms and therapeutic times following cerebral ischemic reperfusion injury. OBJECTIVE:To explore the neuroprotective effects and ideal treatment window for picroside II treatment of middle cerebral artery occlusion and reperfusion injury in rats. DESIGN,TIME AND SETTING:A randomized,controlled,animal experiment was performed at Institute of Cerebrovascular Diseases,Qingdao University Medical College from September 2008 to May 2009. MATERIALS:Picroside Ⅱ was purchased from Tianjin Kuiqing Medical Technology,China. METHODS:A total of 165 adult,healthy,male,Wistar rats were randomly assigned to sham-surgery (n = 15),model (n = 75),and treatment groups (n = 75). Rats in the model and treatment groups underwent middle cerebral artery occlusion and reperfusion through the use of an intraluminal monofilament suture on the left external-internal carotid artery. The treatment group was injected with 1.0% picroside Ⅱ (10 mg/kg) into the tail vein,and the model and sham-surgery groups were injected with 0.1 mol/L phosphate buffered saline (250 μL). MAIN OUTCOME MEASURES:Neurological functional scores were evaluated using the Longa's method; cerebral infarction volume was detected through the use of tetrazolium chloride staining; cellular apoptosis was determined through the use of the in situ end-labeling method; aquaporin-4 expression was measured using fluorescence labeling analysis and reverse transcription polymerase chain reaction technique. RESULTS:At 0.5 hour following cerebral ischemic injury,neurological functional scores were low,and a small infarction focus was detected in the ischemic cortex of the model group. Along with prolonged ischemia and an increased number of apoptosis-positive cells,AQP-4 mRNA and protein expression was increased. At 1-2 hours after ischemia,neurological scores and infarction sizes were significantly increased in the model group. Apoptotic-positive cells were widespread in the ipsilateral cortex and striatum. In addition,AQP-4 mRNA and protein expression levels were increased. Picroside Ⅱ treatment significantly decreased neurological scores and infarction volume,and reduced AQP-4 mRNA and protein expression levels compared with the model group (P < 0.05 or P < 0.01). At 1 hour after ischemia,the therapeutic effect of picroside Ⅱ was notable (P < 0.01). CONCLUSION:Picroside Ⅱ played a protective role in cerebral ischemic reperfusion injury by inhibiting apoptosis and regulating AQP-4 expression. The best therapeutic time window was 1 hour after cerebral ischemic reperfusion.展开更多
文摘Objective: To characterize the expression of aquaporin-4 (AQP4), one of the aquaporins (AQPs), in human brain specimens from patients with traumatic brain injury or brain tumors. Methods: Nineteen human brain specimens were obtained from the patients with traumatic brain injury, brain tumors, benign meningioma or early stage hemorrhagic stroke. MRI or CT imaging was used to assess brain edema. Hematoxylin and eosin staining were used to evaluate cell damage. Immunohistochemistry was used to detect the AQP4 expression. Results: AQP4 expression was increased from 15h to at least 8 d after injury. AQP4immunoreactivity was strong around astrocytomas, ganglioglioma and metastatic adenocarcinoma. However, AQP4 immunoreactivity was only found in the centers of astrocytomas and ganglioglioma, but not in metastatic adenocarcinoma derived from lung.Conclusion: AQP4 expression increases in human brains after traumatic brain injury, within brain-derived tumors, and around brain tumors.
基金supported by the National Natural Science Foundation of China,No.81271286 to YUAN Fang and No.81228009 to YANG Shao Hua
文摘Objective To investigate the role of extracellular signal-regulated kinase1/2(ERK1/2) pathway in the regulation of aquaporin 4(AQP4) expression in cultured astrocytes after scratch-injury. Methods The scratch-injury model was produced in cultured astrocytes of rat by a 10-μL plastic pipette tip. The morphological changes of astrocytes and lactate dehydrogenase(LDH) leakages were observed to assess the degree of scratch-injury. AQP4 expression was detected by immunofluorescence staining and Western blot, and phosphorylated-ERK1/2(p-ERK1/2) expression was determined by Western blot. To explore the effect of ERK1/2 pathway on AQP4 expression in scratch-injured astrocytes, 10 μmol/L U0126(ERK1/2 inhibitor) was incubated in the medium at 30 min before the scratch-injury in some groups. Results Increases in LDH leakage were observed at 1, 12, and 24 h after scratch-injury, and AQP4 expression was reduced simultaneously. Decrease in AQP4 expression was associated with a significant increase in ERK1/2 activation. Furthermore, pretreatment with U0126 blocked both ERK1/2 activation and decrease in AQP4 expression induced by scratch-injury. Conclusion These results indicate that ERK1/2 pathway down-regulates AQP4 expression in scratch-injured astrocytes, and ERK1/2 pathway might be a novel therapeutic target in reversing the effects of astrocytes that contribute to traumatic brain edema.
基金supported by the National Natural Science Foundation of China, No. 30960399, 81160181
文摘To investigate the effects of mRNA interference on aquaporin-4 expression in swollen tissue of rats with ischemic cerebral edema, and diagnose the significance of diffusion-weighted MRI, we injected 5 μL shRNA- aquaporin-4 (control group) or siRNA- aquaporin-4 solution (1:800) (RNA interference group) into the rat right basal ganglia immediately before occlusion of the middle cerebral artery. At 0.25 hours after occlusion of the middle cerebral artery, diffusion-weighted MRI displayed a high signal; within 2 hours, the relative apparent diffusion coefficient decreased markedly, aquaporin-4 expression increased rapidly, and intracellular edema was obviously aggravated; at 4 and 6 hours, the relative apparent diffusion coefficient slowly returned to control levels, aquaporin-4 expression slightly increased, and angioedema was observed. In the RNA interference group, during 0.25- 6 hours after injection of siRNA- aquaporin-4 solution, the relative apparent diffusion coefficient slightly fluctuated and aquaporin-4 expression was upregulated; during 0.5-4 hours, the relative apparent diffusion coefficient was significantly higher, while aquaporin-4 expression was significantly lower when compared with the control group, and intracellular edema was markedly reduced; at 0.25 and 6 hours, the relative apparent diffusion coefficient and aquaporin-4 expression were similar when compared with the control group; obvious angioedema remained at 6 hours. Pearson's correlation test results showed that aquaporin-4 expression was negatively correlated with the apparent diffusion coefficient (r = -0.806, P < 0.01). These findings suggest that upregulated aquaporin-4 expression is likely to be the main molecular mechanism of intracellular edema and may be the molecular basis for decreased relative apparent diffusion coefficient. Aquaporin-4 gene interference can effectively inhibit the upregulation of aquaporin-4 expression during the stage of intracellular edema with time-effectiveness. Moreover, diffusion-weighted MRI can accurately detect intracellular edema.
基金supported by the Eleventh-Five Major Subjects of Nanjing Military Area Command,No.06Z19the Military Medical Science and Technology Innovation Foundation in 2009,No.09Z009
文摘In the present study, rabbits were treated with hyperbaric oxygen for 1 hour after detonator-blast-induced craniocerebral injury. Immunohistochemistry showed significantly reduced aquaporin 4 expression and adrenocorticotropic hormone expression in the pituitary gland of rabbits with craniocerebral injury. Aquaporin 4 expression was positively correlated with adrenocorticotropic hormone expression. These findings indicate that early hyperbaric oxygen therapy may suppress adrenocorticotropic hormone secretion by inhibiting aquaporin 4 expression.
基金supported by the National Natural Science Foundation of China,No.30960399a grant from Hainan Provincial International Cooperation Project of China,No.Qiongke(2012)65a grant from Hainan Provincial Health Department Project of China,No.2011-SWK-10-136/Qiongwei2011-65
文摘Aquaporin-4 regulates water molecule channels and is important in tissue regulation and water transportation in the brain. Upregulation of aquaporin-4 expression is closely related to cellular edema after early cerebral infarction. Cellular edema and aquaporin-4 expression can be determined by measuring cerebral infarct area and apparent diffusion coefficient using diffusion-weighted imaging(DWI). We examined the effects of silencing aquaporin-4 on cerebral infarction. Rat models of cerebral infarction were established by occlusion of the right middle cerebral artery and si RNA-aquaporin-4 was immediately injected via the right basal ganglia. In control animals, the area of high signal intensity and relative apparent diffusion coefficient value on T2-weighted imaging(T2WI) and DWI gradually increased within 0.5–6 hours after cerebral infarction. After aquaporin-4 gene silencing, the area of high signal intensity on T2 WI and DWI reduced, relative apparent diffusion coefficient value was increased, and cellular edema was obviously alleviated. At 6 hours after cerebral infarction, the apparent diffusion coefficient value was similar between treatment and model groups, but angioedema was still obvious in the treatment group. These results indicate that aquaporin-4 gene silencing can effectively relieve cellular edema after early cerebral infarction; and when conducted accurately and on time, the diffusion coefficient value and the area of high signal intensity on T2 WI and DWI can reflect therapeutic effects of aquaporin-4 gene silencing on cellular edema.
基金Supported by a Grant from Zhejiang Provincial Health Department, No. 2007A057
文摘Ammonia induces astrocyte swelling, which is strongly associated with overexpression of aquaporin-4. However, the mechanisms by which ammonia induces astrocyte swelling, and subsequently upregulating aquaporin-4 expression, remain unknown. In the present study, astrocytes were cultured in vitro and exposed to ammonium chloride (NH4Cl), followed by propofol, protein kinase C agonist, or antagonist, respectively. Astrocyte morphology was observed by light microscopy, and aquaporin-4 expression was detected by western blot analysis. Results showed that propofol or protein kinase C agonist significantly attenuated the degree of NH4Cl-induced astrocyte swelling and inhibited increased aquaporin-4 expression. Propofol treatment inhibited aquaporin-4 overexpression in cultured astrocyte induced by NH4Cl; protein kinase C pathway activation is potentially involved.
基金the National Natural Science Foundation of China,No. 30873391
文摘BACKGROUND:Aquaporin-4 (AQP-4) over-expression following cerebral ischemia results in cerebral edema. Picroside Ⅱ has been shown to exhibit a neuroprotective effect on neuronal apoptosis. However,few reports have addressed the neuroprotective mechanisms and therapeutic times following cerebral ischemic reperfusion injury. OBJECTIVE:To explore the neuroprotective effects and ideal treatment window for picroside II treatment of middle cerebral artery occlusion and reperfusion injury in rats. DESIGN,TIME AND SETTING:A randomized,controlled,animal experiment was performed at Institute of Cerebrovascular Diseases,Qingdao University Medical College from September 2008 to May 2009. MATERIALS:Picroside Ⅱ was purchased from Tianjin Kuiqing Medical Technology,China. METHODS:A total of 165 adult,healthy,male,Wistar rats were randomly assigned to sham-surgery (n = 15),model (n = 75),and treatment groups (n = 75). Rats in the model and treatment groups underwent middle cerebral artery occlusion and reperfusion through the use of an intraluminal monofilament suture on the left external-internal carotid artery. The treatment group was injected with 1.0% picroside Ⅱ (10 mg/kg) into the tail vein,and the model and sham-surgery groups were injected with 0.1 mol/L phosphate buffered saline (250 μL). MAIN OUTCOME MEASURES:Neurological functional scores were evaluated using the Longa's method; cerebral infarction volume was detected through the use of tetrazolium chloride staining; cellular apoptosis was determined through the use of the in situ end-labeling method; aquaporin-4 expression was measured using fluorescence labeling analysis and reverse transcription polymerase chain reaction technique. RESULTS:At 0.5 hour following cerebral ischemic injury,neurological functional scores were low,and a small infarction focus was detected in the ischemic cortex of the model group. Along with prolonged ischemia and an increased number of apoptosis-positive cells,AQP-4 mRNA and protein expression was increased. At 1-2 hours after ischemia,neurological scores and infarction sizes were significantly increased in the model group. Apoptotic-positive cells were widespread in the ipsilateral cortex and striatum. In addition,AQP-4 mRNA and protein expression levels were increased. Picroside Ⅱ treatment significantly decreased neurological scores and infarction volume,and reduced AQP-4 mRNA and protein expression levels compared with the model group (P < 0.05 or P < 0.01). At 1 hour after ischemia,the therapeutic effect of picroside Ⅱ was notable (P < 0.01). CONCLUSION:Picroside Ⅱ played a protective role in cerebral ischemic reperfusion injury by inhibiting apoptosis and regulating AQP-4 expression. The best therapeutic time window was 1 hour after cerebral ischemic reperfusion.
