七氟烷预处理对脑缺血-再灌注损伤大鼠脑组织热休克蛋白70和27表达的影响

【目的】观察七氟烷对大鼠局灶性脑缺血-再灌注时脑组织热休克蛋白（HSP）70和27表达的影响，以探讨其脑保护的机制。【方法】采用大脑中动脉线栓法建立大鼠局灶性脑缺血-再灌注模型。30只雄性SD大鼠，随机分为假手术组（Sham组）、缺血-再灌注组（I-R组）和七氟烷组（S组），每组10只。大鼠脑缺血60min，然后进行再灌注。S组在脑缺血前30min吸入氧气＋2．4％七氟烷60rain。Sham组和I-R组吸入氧气。缺血60min，再灌注24h后处死大鼠，取缺血侧顶叶皮层脑组织，采用Western-blot法检测HSP_70和HSP-27蛋白的表达水平。【结果】局灶性脑缺血再灌注后，HSP-70和HSP-27蛋白的表达增加（P〈o．01），应用七氟烷预处理能显著地促进脑缺血-再灌注后脑组织中HSP-70和HSP-27蛋白的表达（P〈0．01）。【结论】七氟炕能上调大鼠局灶性脑缺血-再灌注时HSP70和HsPL27的表达，这可能是其脑保护作用的部分机制。

Effect of Sevoflurane Preconditioning on HSP-70 and 27 Protein after Focal Cerebral Ischemia-reperfusion in Rats

Objective] To investigate the effect of preconditioning with sevoflurane on expression of HSP 70 and 27 protein after focal cerebral isehemia-reperfusion （I/R） and the mechanism of neuroprotection by in halational anesthetics. Methods] Thirty male SD rats aged 3-4 months weighing 250-300 g were randomly divided into 3 groups including Sham group（ n = 10）, sevoflurane group（ n = 10） and isehemia reperfusion group（ n =10）. The focal cerebral ischemia-reperfusion model was established by thread embolism of middle cerebral artery. Sevoflurane preconditioning was induced at 30rain before brain ischemia by exposing the ani- mals to 2.4% sevoflurane plus oxygen for 60min. The animals in ischemia reperfusion group and Sham group were exposed to oxygen for 60 min at 30 rain before MCAO. Rats were subjected to focal ischemia for 60min by right middle cerebral artery occlusion （MCAO） and then received reperfusion. At 24 hours after reperfu sion, the rats were decapitated, and the expression of HSP 70 and 27 protein in ischemic cortex was examined by using in Western-blot method. Results]Compared with Sham group, the expression of HSP 70 and 27 protein in ischemic cortex increased significantly after focal cerebral isehemia-reperfusion in isehemia-reperfu sion group（ P d0.01）. Compared with ischemia-reperfusion group, sevoflurane preconditioning significantly enhanced the expression of HSP-70 and 27 protein in ischemic cortex （ P〈0.01）. Conclusion]This study demonstrates that sevoflurane preconditioning enhances the expression of HSP-70 and 27 during focal cerebral ischemia-reperfusion, which may be one of the mechanisms of its neuroprotection.