表没食子儿茶素没食子酸酯对大鼠心肌缺血再灌注损伤的保护作用

目的观察表没食子儿茶素没食子酸酯(EGCG)对大鼠心肌缺血再灌注损伤的保护作用。方法结扎左冠状动脉前降支30mm再灌注60m in复制大鼠心肌缺血再灌注模型,实验分假手术组、缺血再灌注组(IR)、EGCG1(10mg.kg-1)、EGCG2(20mg.kg-1)和丹参(SM,1.0g.kg-1)治疗组。用心功能分析系统测定左室心功能,按试剂盒说明测定血浆SOD,MDA,LDH和CK水平,用TUNEL法检测凋亡细胞,SABC免疫组化法检测凋亡相关基因bc l-2与bax的蛋白表达。结果①缺血再灌注期间,IR组大鼠左室LVSP,±dp/dtm ax呈进行性下降,LVEDP则进行性升高(与假手术组比,P<0.01),EGCG组虽有相似的变化趋势,但明显较缓(与IR组比,P<0.01)。②IR组大鼠血浆SOD水平显著降低;MDA,LDH与CK水平显著升高。EGCG组SOD水平则明显升高;MDA,LDH与CK水平明显降低(P<0.01)。③IR组心肌凋亡细胞明显,bc l-2与bax蛋白表达增多,bc l-2/bax值下降;EGCG组凋亡细胞减少,bc l-2蛋白表达显著增多,bax则明显减少,bc l-2/bax值升高(P<0.01)。结论EGCG通过提高机体清除自由基能力减轻心肌细胞损伤和抑制心肌细胞凋亡而改善心功能,对大鼠心肌缺血再灌注损伤具有保护作用。

The protective role of epigallocatechin gallate on myocardial ischemia reperfusion injury in rats

OBJECTIVE To observe the protective effect of epigallocatechin gallate(EGCG) on myocardial ischemia reperfusion injury in rats.METHODS The left anterior descending branch of coronary artery was ligated for 30min and reperfused 60min to make the myocardial ischemia reperfusion model in rats.50 male wistar rats were averagely divided into five groups sham,ischemia reperfusion(IR),treated with EGCG(10mg/kg and 20mg/kg) and saliva milfiorrhizae(SM,1.og/kg).The left cardiac function was measured by the analysis system.The levels of SOD,MDA,LDH and CK in plasma were measured according to the directions of reagent box.The apoptosis cardiomyocyte was shown by TUNEL method,and the expression of bcl-2 and bax were shown by immunohistochermistrial method. RESULTS Compared with the sham group,the left cardiac function was decreased during myocardial ischemia reperfusion(P<0.01),the level of SOD in plasma was decreased,while the levels of MDA,LDH and CK were increased in IR group(P<0.01),however,the changes above were significantly improved in EGCG group(P<0.01).There were many apoptosis cardiomyocytes in IR group,and the expression of bcl-2 and bax were increased,the ratio of bcl-2/bax reduced.But in EGCG group,the apoptosis and the expression of bax were less,the expression of bcl-2 was higher than IR group,and the ratio of bcl-2/bax was obviously risen.CONCLUSION EGCG can enhance the ability of inhibiting myocardial lipid peroxidation to alleviate myocardial injury,inhibit cardiomyocyte apoptosis and improve cardiac function.