葡萄糖调节蛋白78对脑缺血再灌注后神经细胞凋亡的影响

目的 通过体内体外实验探讨内质网伴侣蛋白-葡萄糖调节蛋白(GRP)78对缺血再灌注后神经细胞凋亡的影响.方法 体内实验采用大鼠大脑中动脉线栓模型,应用免疫组织化学、Western blot和RT-PCR方法检测脑缺血再灌注后缺血周围区GRP78表达的动态变化;体外实验通过原代培养的海马神经元建立脑缺血再灌注模型,Western blot方法观察去糖去氧及恢复糖氧后GRP78表达的变化,并运用2脱氧葡萄糖诱导GRP78高表达,观察对神经细胞凋亡的影响.结果 体内实验:与假手术组相比,脑缺血再灌注后GRP78表达明显增强,再灌注12 h达高峰(mRNA:0.7367±0.0651,F-477.160,P<0.01;蛋白:0.8129±0.0748,F=39.857,P<0.01).体外实验:经2脱氧葡萄糖预处理高表达GRP78的神经细胞活力明显增强(与单纯去糖去氧组相比,细胞活力增加了39.22%±0.44%,t=46.374,P<0.01),凋亡细胞减少(与单纯去糖去氧组相比,凋亡细胞数减少16.60±1.02,t=7.530,P<0.01).结论 脑缺血再灌注启动内质网应激反应,与神经细胞凋亡有关;诱导GRP78高表达可以减轻缺血再灌注性神经元的损伤和凋亡.

Effect of glucose regulated protein 78 on neuronal apoptosis after cerebral ischemia reperfusion injury in rats

Objective To explore the effect of glucose regulated protein (GRP)78 on the neuronal apoptosis after cerebral ischemia reperfusion injury in rats. Methods Middle cerebral artery ischemia reperfusion rat's models were used with the modified filament method. The expression of GRP78 in the ischemic penumbra tissue was detected by RT-PCR, Western blot and immunohistochemistry at different time points. Primary cultured rat's neurons were exposed to hypoxia and subsequently reoxygenation. Western blot was used to investigate the expression of GRP78. The changes of the neuronal apoptosis after overexpression of GRP78 induced by 2-deoxyglucose were detected. Results The expression of GRP78 in the ischemic penumbra tissue in model group was significantly increased (mRNA : 0.7367±0.0651, F= 477.160, P < 0.01 ; Protein : 0. 8129±0. 0748, F=39.857, P < 0.01). The neuronal survival status was increased after overpression of GRP78 (increased by 39.22% ± 0. 44%, t=46.374, P < 0.01) while the neuronal apoptosis was decreased (decreased by 16.60±1.02, t=7.530, P <0.01). Conclusion Focal cerebral ischemia reperfusion can induce endoplasmic reticulum stress which plays a role in the neuronal apoptosis. The increased expression of GRP78 may protect the ischemic tissue from neuronal apoptosis.