小鼠短暂前脑缺血海马中半胱天冬酶-３酶原表达的变化

通过测定脑缺血再灌注时海马中半胱天冬酶-3酶原(procaspase-3)的表达变化, 从细胞凋亡的角度探讨脑缺血再灌注损伤的分子生物学机制及procaspase-3的活化机制.将C57BL/6N小鼠随机分为假手术组(正常对照组)、缺血再灌注组(I/R组), 后者夹闭双侧颈总动脉20 min后再通血流, 建立前脑缺血再灌注模型, 分别于再灌注6 h、12 h、24 h和48 h取海马.采用蛋白免疫印迹(Western blotting)方法检测海马中procaspase-3的表达变化.结果显示, 12 h I/R及24hI/R组海马中总procaspase-3水平与假手术组相比有明显升高, 且差异有统计学意义(P<0.05),24 h I/R组海马中去磷酸化水平与假手术组相比有明显升高, 且差异有统计学意义(P<0.05),而各组procaspase-3磷酸化水平与假手术组相比差异无统计学意义.结果提示, 脑缺血再灌注损伤诱发procaspase-3表达增加,其中procaspase-3去磷酸化水平高明显, 提示脑缺血再灌注损伤可能诱发procaspase-3去磷酸化, 继而促进procaspase-3转化为活性形式.

Expression of Procaspase-3 in the Mouse Hippocampus after Transient Forebrain Ischemia

The expression of procaspase-3 in hippocampus following transient forebrain ischemia was explored,and the possible relationship of ischemia/reperfusion and procaspase-3 activation was observed.C57BL/6N mice were divided into two groups: sham-operated group(control),and ischemia/reperfusion group(I/R group).Transient forebrain ischemia was induced by bilateral common carotid occlusion(BCCAO) for 20 minutes.Hippocampus sections were obtained at reperfusion time points of 6 hours,12 hours,24 hours and 48 hours respectively after 20 minutes of ischemia.Western blotting was used to detect the level of procaspase-3.Total procaspase3 level increased in hippocampus at reperfusion time points of 12 hours and 24 hours post-BCCAO,and the dephosphorylated procaspase-3 level increased in hippocampus at reperfusion time point of 24 hours post-BCCAO.The increased expressions were significant(P<0.05) when compared with expression level in sham-operated mice. While the phosphorylated level did not change significantly.These data indicated that ischemia/reperfusion upregulated procaspase-3.Further observation found out that the increase of dephosphorylated form of procaspase-3 was higher than the increase of phosphorylated form of procaspase-3 upon cerebral ischemia/reperfusion injury,which indicated that cerebral ischemia/reperfusion injury possibly induced procaspase-3 dephosphorylate, and then activated procaspase-3 into active caspase-3.