α7烟碱受体拮抗剂对Aβ蛋白诱导损伤的PC12细胞保护作用的研究

The study on protective effect of α7 nicotinic antagonist on PC12 cell injury induced by β-Amyloid peptides.

目的观察α7烟碱受体拮抗剂对Aβ蛋白诱导损伤的PC12细胞远期影响,探讨其细胞保护的作用。方法采用高分化的PC12细胞为研究对象,以Aβ25-35制作细胞损伤模型,以烟碱受体激动剂(尼古丁)和α7烟碱受体拮抗剂(甲基牛扁亭碱)进行预处理。试验分为4组,分别是:对照组(蒸馏水)、模型组(Aβ25-35)、尼古丁组(尼古丁和Aβ25-35)、甲基牛扁亭碱组(甲基牛扁亭碱和Aβ25-35)。通过MTT比色法在多个时间点观察药物对细胞活力影响的动态变化,在此基础上采用流式细胞仪检测药物对细胞凋亡和坏死的影响。结果在所有时间点,模型组的细胞活力均显著低于对照组,凋亡和坏死率均高于对照组(P<0.01)。药物作用36～60h,尼古丁组的细胞活力显著高于模型组和甲基牛扁亭碱组(P<0.05),凋亡和坏死率较低(P<0.01);甲基牛扁亭碱组细胞活力及凋亡和坏死率与模型组差异无统计学意义。在药物作用84h后,与模型组和尼古丁组相比,甲基牛扁亭碱组细胞活力显著升高,凋亡和坏死率显著降低(P<0.01)。结论随着作用时间的延长(84h),烟碱受体激动剂(尼古丁)对PC12细胞的保护作用逐渐消失,而α7烟碱拮抗剂(甲基牛扁亭碱)逐渐显现出细胞保护作用。

Objective To observe the long term effect of chronic administration of a7 nicotinic antagonist on PC12 cells injury induced by β-Amyloid peptides. Methods Well-differentiated PC12 cells were exposed to Aβ25-35 to create PC12 cell injury model and nicotine and methyllyeaeonitine were administrated before PC12 cell injury. The experimental groups were divided as follows： control （Distilled Water）, model group （Aβ25-35）, nicotine group （nicotine and Aβ25-35） and methyllyeaeonitine group （methyllycaconitine and Aβ25-35）. The cellar viability was detected using MTT ehromatometry and the apoptosis and necrosis was detected by flow cytometer. Results Com- pared with control group, the cellular viability was decreased and apoptotic and necrotic rates were increased at every phase in model group （P 〈 0.01）. Compared with model and methyllyeaeonitine groups, the cellular viability was increased （P 〈 0.05） and apoptotie and necrotic rate were decreased in nicotine group （P 〈 0.01） between 36 and 60 h following treatment. There were no significant changes in cellular viability and apoptotie as well as necrotic rates between model and methyllycaeonitine groups between 36 to 60 h following treatment. When treatment was prolonged to 48 h, there were no significant differences in cellular viability and apoptotic as well as necrotic rates between nicofine and model groups. However, treatment with Methyllycaconitine for 48 h significantly increased cell viability and decreased apoptotic and necrotic rates compared with either model or nicotine groups （P 〈 0.01）. Conchlsions When treatment is prolonged, the protective effect of nicotinic agonist（nicotine） decreases whereas the protective effect of a7 nicotinic antagonist （methyllycaconitine） increases.