Objective. The experiment was designed to study the association of cerebral ischemia and reperfusion with endothelin- 1 (ET- 1) gene expression of rat brains and time-dependent changes of ET- 1 gene expression during...Objective. The experiment was designed to study the association of cerebral ischemia and reperfusion with endothelin- 1 (ET- 1) gene expression of rat brains and time-dependent changes of ET- 1 gene expression during cerebral ischemia.Materials and methods. Thirty- three male SD rats were divided into dot blot hybridization(n = 27) and in silu hybridization groups(n= 6). The focal cerebral ischemia and reperfusion models were made with suture embolism of middle cerebral artery. Dot blot hybridization groups were redivided into control and ischemic subgroups (ischemia for 0. 5 , 1 , 1. 5 , 3 , 6 , 12 , 24 , 48 and 72 h respectively). In situ hybridization groups were redivided into ischemia and reperfusion groups. After 24 h ischemia and 24 h reperfusion,ET1 gene expressions were investigated with in situ hybridization and the resuhs were analyzed with IBAS 2000 Image Analysis System.Results. Dot blot hybridization showed that ET-1 mRNA of cerebral cortex and caudate- putamen was increased at 6 h of ischemia and reached peak at 24 h (3. 9 and 3. 7 fold respectively) ,and at 72 h of ischemia it remained at high levels(3. 5 and 2. 1 fold respectively). In silu hybridization showed that the levels of ET- 1 mRNA of cerebral cortex and caudate-putamen were also markedly increased both in 24 h ischemia and 24 h reperfusion groups (P<0. 01 , P<0. 05 respectively) .Conclusions. ET-1 gene expression in focal ischemic brain tissue were markedly and progressively increased during cerebral ischemia and reperfusion and downregulation of ET- 1 gene expression may be a new approach to the treatment of ischemic cerebrovascular diseases.展开更多
Objective： To investigate a possible mechanism responsible for anti-apoptotic effects of melatonin and provide theoretical evidences for clinical therapy. Methods： lschemia-reperfusion mediated neuronal cell injury ...Objective： To investigate a possible mechanism responsible for anti-apoptotic effects of melatonin and provide theoretical evidences for clinical therapy. Methods： lschemia-reperfusion mediated neuronal cell injury model was constructed in cerebellar granule neurons （CGNs） by deprivation of glucose, serum and oxygen in media. After ischemia, melatonin was added to the test groups to reach differential concentration during reperfusion. DNA fragmentation, mitochondrial transmembrane potential, mitochondrial cytochrome c release and caspase-3 activity were observed after subjecting cerebellar granule neurons to oxygen-glucose deprivation （OGD）. Results： The results showed that OGD induced typical cell apoptosis change, DNA ladder and apoptosis-related alterations in mitochondrial functions including depression of mitochondrial transmembrane potential （its maximal protection ratio was 73.26%） and release of cytochrome c （its maximal inhibition ratio was 42.52%） and the subsequent activation of caspase-3 （its maximal protection ratio was 59.32%） in cytoplasm. Melatonin reduced DNA damage and inhibited release of mitochondrial cytochrome c and activation of caspase-3. Melatonin can strongly prevent the OGD-induced loss of the mitochondria membrane potential. Conclusion： Our findings suggested that the direct inhibition of mitochondrial pathway might essentially contribute to its anti-apoptotic effects in neuronal ischemia-reperfiusion.展开更多
文摘Objective. The experiment was designed to study the association of cerebral ischemia and reperfusion with endothelin- 1 (ET- 1) gene expression of rat brains and time-dependent changes of ET- 1 gene expression during cerebral ischemia.Materials and methods. Thirty- three male SD rats were divided into dot blot hybridization(n = 27) and in silu hybridization groups(n= 6). The focal cerebral ischemia and reperfusion models were made with suture embolism of middle cerebral artery. Dot blot hybridization groups were redivided into control and ischemic subgroups (ischemia for 0. 5 , 1 , 1. 5 , 3 , 6 , 12 , 24 , 48 and 72 h respectively). In situ hybridization groups were redivided into ischemia and reperfusion groups. After 24 h ischemia and 24 h reperfusion,ET1 gene expressions were investigated with in situ hybridization and the resuhs were analyzed with IBAS 2000 Image Analysis System.Results. Dot blot hybridization showed that ET-1 mRNA of cerebral cortex and caudate- putamen was increased at 6 h of ischemia and reached peak at 24 h (3. 9 and 3. 7 fold respectively) ,and at 72 h of ischemia it remained at high levels(3. 5 and 2. 1 fold respectively). In silu hybridization showed that the levels of ET- 1 mRNA of cerebral cortex and caudate-putamen were also markedly increased both in 24 h ischemia and 24 h reperfusion groups (P<0. 01 , P<0. 05 respectively) .Conclusions. ET-1 gene expression in focal ischemic brain tissue were markedly and progressively increased during cerebral ischemia and reperfusion and downregulation of ET- 1 gene expression may be a new approach to the treatment of ischemic cerebrovascular diseases.
文摘Objective： To investigate a possible mechanism responsible for anti-apoptotic effects of melatonin and provide theoretical evidences for clinical therapy. Methods： lschemia-reperfusion mediated neuronal cell injury model was constructed in cerebellar granule neurons （CGNs） by deprivation of glucose, serum and oxygen in media. After ischemia, melatonin was added to the test groups to reach differential concentration during reperfusion. DNA fragmentation, mitochondrial transmembrane potential, mitochondrial cytochrome c release and caspase-3 activity were observed after subjecting cerebellar granule neurons to oxygen-glucose deprivation （OGD）. Results： The results showed that OGD induced typical cell apoptosis change, DNA ladder and apoptosis-related alterations in mitochondrial functions including depression of mitochondrial transmembrane potential （its maximal protection ratio was 73.26%） and release of cytochrome c （its maximal inhibition ratio was 42.52%） and the subsequent activation of caspase-3 （its maximal protection ratio was 59.32%） in cytoplasm. Melatonin reduced DNA damage and inhibited release of mitochondrial cytochrome c and activation of caspase-3. Melatonin can strongly prevent the OGD-induced loss of the mitochondria membrane potential. Conclusion： Our findings suggested that the direct inhibition of mitochondrial pathway might essentially contribute to its anti-apoptotic effects in neuronal ischemia-reperfiusion.
