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Objective To observe the effect of focal cerebral ischemic preconditioning on the expression of glial fibrillary acidic protein (GFAP) and to investigate the significance of astrocyte activation in cerebral ischemic tolerance.Methods Thirty-six healthy male SpragueDawley rats were randomly divided into reischenmic,ischemic and control groups (n = 12 in each group) after ischemic preconditioning.The former two groups received 10 minutes middle cerebral artery occlusion (MCAO) preconditioning or sham operation 3 days before the 2-hour MCAO.The rats were killed 24 hours after the second MCAO.The control group only receivedthe two sham operations with an interval of three days.The infarct volume,histopathological changes,and GFAP expression in each group were compared.Results The infarct volume after ischemic preconditioning in the reischenmic and ischemic groups was 136.85 ± 14.51 mm3and 281.37 ± 29.93 mm3 respectively.The former was significantly reduced 53.15%compared to the latter (P =0.007).At the same time,neuronal degeneration and necrosis was reduced significantly,and GFAP expression was upregulated significantly (the mean absorbance for immunohistochemical staining in both groups was 102.66 ± 8.39 and 86.28 ± 6.19respectively,P = 0.009) after ischemic preconditioning in the reischemic group.Conclusions Focal ischemic preconditioning may induce brain ischemic tolerance and promote GFAP expression.The activation of astrocytes may be one of the mechanisms of cerebral ischemic tolerance.
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Objective To investigate the effect of focal cerebral ischemic preconditioning (IPC) on brain edema and the expression of nuclear factor-?B( NF-?B) and its target gene MMP-9. Methods Forty-five SD rats were divided into 3 groups in which control group received sham surgery only, and the other two groups received 2 hours of middle cerebral artery occlusion (MCAO) followed by 22 hours of reperfusion with or without 10 minutes of IPC 3 days before. Brain water content, expression of NF-?B and MMP-9 mRNA were evaluated in each group by wet-dry weight method, immunohistochemistry staining and RT-PCR. Results Compared with the SS group, there was a lower NF-?B immunoreactivity and MMP-9 mRNA level (16 098.2?1 265.3 vs 23 565.8?1 978.4,50.7% vs 84.1%, P
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Objective To investigate the influence of focal ischemic preconditioning on the expression of heat shock protein 70(HSP70) and ischemic tolerance Methods 42 SD rats were divided into 3 groups in which control group received sham operation only, and the other two groups received 2 hours of middle cerebral artery occlusion(MCAO) followed by 22 hours of reperfusion with or without 10 minutes of ischemic preconditioning 3 days before Infarct volume and HSP70 immunoreactivity were evaluated in each group Results Compared with the sham operated group, there was a smaller infarct volume( P
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Objective To investigate the influence of ozagrel sodium (OS) on cerebral ischemic tolerance in rat induced by focal ischemic preconditioning (IPC) and on expression of nuclear factor ?B (NF ?B) in rats Methods Fourty five rats were divided into 3 groups The animals were subjected to 2 h middle cerebral artery occlusion (MCAO) 3 days after 10 min IPC, IPC+OS and sham surgery (SS) respectively. After 22 h reperfusion, the rats were killed and the infarct volume, brain water content and NF ?B immunoreactivity were compared among 3 groups. Results Compared with IPC+ MCAO group, there were a furtber decrements in farct volume (93 75?13 40 vs 130 92?14 59, P