内质网应激相关分子葡萄糖调节蛋白78及增强子结合蛋白同源蛋白在高血压大鼠全脑缺血海马区的表达变化

摘要

Objective:To observe expressions of glucose-regulated protein 78 (GRP78) and glucose-regulated protein CAAT/enhanced Ⅰ-binding protein homologous protein (CHOP) in the hippocampus of the rats with normal blood pressure and spontaneously hypertensive rats with cerebral ischemia/reperfusion,and to explore the possible effects that hypertension aggravated global cerebral ischemia reperfusion injury.Methods:60 male Wistar-Kyoto (WKY) rats with normal blood pressure were randomly divided into a sham operation group (sham) and a global cerebral ischemia-reperfusion group (ischemia/reperfusion,I/R) ; Another 30 male rats with spontaneous hypertension were used as a global cerebral ischemia-reperfusion group (SHR+I/R).Global cerebral ischemia model was formed by improved four-vessel occlusion as described according to the description of Pulsinelli's method.6,24,48 hours after injury,the morphology of the neurons in the hippocampal region was observed by H-E staining;the expressions of GPR78 and CHOP were detected by immunohistochemistry and Western blotting; Behavior tests were performed with eight-arm maze at 48 h.Results:Compared with the sham group,the neuronal shape was damaged and the number of the survival neurons decreased; the GRP78 expression increased and peaked at 24 h and the CHOP expression increased and peaked at 24 h in I/R group.Compared with I/R group,the number of the survival neurons decreased obviously at each time point in SHR+ IR group; the GRP78 expression significantly increased at 6 h,while significantly decreased at 24,48 h and CHOP expression markedly increased at 6 h and 24 h,while markedly decreased at 48 h; Eight-arm maze test showed that there were significant differences in each of index between SHR+ IR group and I/R group.Conclusion:Hypertension can aggravate vulnerability after global cerebral ischemia reperfusion,which is related to aggravating the down-regulation and up-regulation of CHOP expression.%目的:观察血压正常大鼠和高血压大鼠全脑缺血再灌注后海马区CAAT/增强子结合蛋白同源蛋白(CHOP)、葡萄糖调节蛋白78(GRP78)的表达变化,探讨内质网应激在高血压增加脑缺血再灌注神经易损性中的作用.方法:60只雄性血压正常Wistar-Kyoto(WKY)大鼠随机分为假手术组(Sham)和全脑缺血再灌注组(I/R)；另取30只雄性自发性高血压大鼠为高血压全脑缺血再灌注组(SHR+I/R).应用改良的Pulsineli 4血管阻断(4-VO)法制作全脑缺血再灌注模型.各组分别在术后6、24、48 h,H-E染色观察海马区神经细胞形态变化；免疫组织化学和免疫印迹检测海马区CHOP、GRP78的表达；48 h八臂迷宫检测动物行为学变化.结果:与Sham组比较,I/R组各时间点存活神经元数量降低；GRP78表达增高,24 h达高峰；CHOP表达增高,24 h达高峰,高表达持续至48 h；与I/R组比较,SHR+ IR组各时间点存活神经细胞数量降低；GPR78表达6h增高,24、48h显著减少；6、24 h CHOP表达增高,48 h明显减少；八臂迷宫结果显示SHR+I/R组与I/R组比较,各检测指标变化差异有统计学意义.结论:高血压可增加脑缺血再灌注神经易损性,与加重缺血再灌注后GRP78表达下降、CHOP活体表达增高有关.