β-淀粉样蛋白1-42寡聚体诱导的阿尔茨海默病大鼠海马的Bcl-2表达和caspase-3活性变化

Expression of Bcl-2 and activation of caspase-3 of the hippocampus in Alzheimer＇s disease rat model induced by Aβ1-42 oligomer

目的：研究β-淀粉样蛋白1-42（Aβ1-42）寡聚体诱导痴呆大鼠脑海马区的Bcl-2表达和caspase-3活性变化及其意义.方法：采用Morris水迷宫法筛选出逃避潜伏期少于60 s的60只SD雄性大鼠随机分为4组,即正常对照组、PBS对照组、Aβ1-42纤维组、Aβ1-42寡聚体组.通过脑立体定位仪将Aβ1-42纤维体、Aβ1-42寡聚体注入大鼠右侧脑室,制备AD大鼠模型.RT-PCR法检测大鼠海马Bcl-2 mRNA、caspase-3 mRNA的表达,用免疫印迹测定大鼠海马区Bcl-2蛋白表达和caspase-3活性.结果：与正常对照组及PBS对照组比较,模型组大鼠海马区Bcl-2 mRNA和Bcl-2蛋白表达较低,Aβ1-42纤维组Bcl-2的蛋白表达高于Aβ1-42寡聚体组;Aβ1-42寡聚体组的caspase-3 mRNA表达以及caspase-3蛋白活性高于Aβ1-42纤维组.结论：Aβ1-42寡聚体可下调Bcl-2表达,活化caspase-3.

Objective： To study the expression of Bcl-2 and the activation of caspase-3 of the hippocampus in Alzheimer＇s disease （AD） rat model induced by Aβ1-42 oligomer and its significance. Methods： Morris water maze method was used to screen the experimental animal. 60 rats （the escape latency less than 60 s） were randomly divided into four groups （n= 15） ： a normal group, a PBS control group, Aβ1-42 fiber group and Aβ1-42 oligomers group. The Aβ1-42 fiber body and Aβ1-42 oligomers were injected into rat right cerebral ventricle for preparation AD rat model; PBS control group injected with PBS; normal group without any treatment. RT-PCR method was used to detect the expression of Bcl-2 mRNA and caspase-3 mRNA of the hippocampus in AD rats, and Western blotting assay was used to detect Bcl-2 protein expression and activity of caspase-3 protein in the rat hippocampus. Results： Compared with the normal group and PBS control group, the expression levels of Bcl-2 mRNA and Bcl-2 protein in the hippocampus was down-regulated in the model group rats, the expression level of Bcl-2 protein was higher in Aβ1-42 fiber group than in Aβ1-42 oligomers group; the expression of caspase-3 mRNA and the activity of caspase-3 protein in Aβ1-42 oligomers group was increased compared with the Aβ1-42 fiber group. Conclusion： Aβ1-42 oligomers can reduce Bcl-2 protein expression, and increase the activity of caspase-3 protein.