丙酮酸乙酯对大鼠缺血再灌注心肌Bcl-2、Bax和caspase-3表达的影响

Effects of ethyl pyruvate on myocardial expression of Bcl-2,Bax and Caspase-3 during ischemia/reperfusion in rat.

目的探讨丙酮酸乙酯(EP)对缺血再灌注(I/R)心肌细胞凋亡的可能机制。方法将24只雄性SD大鼠随机分为对照组、I/R组和EP组各8只,均建立Langendorff离体心脏模型,对照组K-H液持续灌流180 min;I/R组平衡灌流30 min,全心停灌30 min,再灌120 min;EP组试验程序与I/R组相同,平衡15 min后和再灌注期间使用含2 mmol/L EP的K-H液。分别以缺口末端标记法及免疫组化法检测各组心肌细胞凋亡指数(AI)及Bcl-2、Bax和caspase-3蛋白表达。结果I/R组AI和Bcl-2、Bax、caspase-3表达水平均明显高于对照组;与I/R组相比,EP组AI和Bax、caspase-3表达水平明显降低,而Bcl-2表达水平明显升高。结论EP可抑制离体大鼠I/R损伤过程中的心肌细胞凋亡,其机制可能为下调Bax、caspase-3表达,上调Bcl-2表达。

[Objective] To study the effects of ethyl pyruvate on cardiomyocyte apoptosis following ischemia reperfusion in vitro and on expression of Bcl-2,Bax and caspase-3. [Methods] Isolated rat hearts were perfused in Langendorff model. Twenty-four male SD rats were randomly divided into 3 groups （n=8,respectively）： control group was perfused with K-H buffer for 180 min. In the ischemia/reperfusion （I/R） group,after 30 min stabilization the injury was induced by 30 min global ischemia followed by 120 min reperfusion. Ethyl pyruvate （EP） group was carried out with the same protocol as the I/R gorup except that it was supplied with K-H buffer containing 2 mmol/L ethyl pyruvate 15 min before ischemia and during reperfusion. Myocardial apoptotic index （AI） was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling （TUNEL） method. Expression of Bcl-2, Bax and caspase-3 in cardiomyocytes was detected by immunohistochemistry method. [Results] Compared with control group, AI and the expression of Bcl-2, Bax and caspase-3 proteins were increased significantly in I/R group; while comparing with I/R group, AI and the expression of Bax,caspase-3 protein were decreased obviously and the expression of Bcl-2 protein was upregulated in EP group（P〈 0. 01）. [Conclusion] Ethyl pyruvate can inhibit cardiomyocytes apoptosis,it may be via upregulating Bcl-2 and downregulating Bax,caspase-3 protein.