细胞凋亡的线粒体信号通路在大鼠缺血延迟预适应抗心肌细胞凋亡机制中的作用

目的：以细胞凋亡的线粒体途径为切入点,探讨心肌缺血延迟预适应抑制心缺血再灌注（MI/R）后细胞凋亡的可能机制.方法：SD大鼠分为正常对照组、假手术组、缺血再灌注组、延迟缺血预处理组.缺血再灌注组采用经典大鼠冠脉结扎,缺血1h,再灌1h.延迟缺血预处理组采用缺血5min,再灌5min,反复循环3次,24h后缺血1h,再灌1h.流式细胞仪测定心肌细胞凋亡率,进行细胞色素C（CytC）和凋亡诱导因子（AIF）的Western blotting分析及Caspase-3活性测定,并利用免疫组织化学染色法检测大鼠心肌HSP70的表达.结果：与缺血再灌注组相比较,心肌缺血预处理24h后可以减少MI/R后心肌细胞凋亡率,抑制CytC和AIF自线粒体向胞浆的释放及caspase-3的活化,上调HSP70蛋白表达.结论：心肌缺血延迟预适应可以减少MI/R造成的细胞凋亡,机制与其诱导HSP70的生成,抑制细胞凋亡的线粒体信号转导途径有关.

Mechanism of delayed preconditioning protects myocardial cell against apoptosis: investigating mitochondria signal pathway of apoptosis

Objective: To investigate the possible mechanism of delayed preconditioning protect of myocardial cell against apoptosis caused by MI/R through mitochondria signal pathway of apoptosis.Method:Sprage-Dawleyt rats were divided into four groups:control, sham, I/R and preconditioning. The rats in I/R group underwent ischemia for 1 hour by classic artery ligation and reperfusion for 1 hour. The rats in delayed preconditioning group underwent three cycles of 5-minute ischemia and 5-minute reperfusion 24 hours prior to the index occlusion. The cell apoptosis was measured by flow cytometry. The CytC and AIF were detected by Western blotting. The Caspase-3 activity was measured and HSP70 protein expression was detected by immunohistochemistry. Result:Myocardial delayed preconditioning decreased apoptosis rate of myocardial cell, inhibited the release of CytC and AIF from mitochondria into cytosol and caspase-3 activation, and up-regulated HSP70 protein level.Conclusion:Myocardial delayed preconditioning can suppress apoptosis caused by MI/R, the mechanism is related to HSP70 production and inhibition of mitochondria signal transduction of apoptosis.