miR-126对急性心肌梗死大鼠心肌细胞凋亡的影响

目的探讨miR-126对急性心肌梗死(AMI)大鼠心肌细胞凋亡的影响。方法通过冠状动脉左前降支结扎大鼠建立AMI模型,随机分为AMI组、miR-126 mimics negative control(NC)组及miR-126组,其中NC组及miR-126组分别采用心肌组织局部注射慢病毒转染miR-126 mimics NC及miR-126 mimics,另外假手术组采用冠状动脉左前降支穿线不结扎。记录大鼠心脏功能,TCC法及原位末端凋亡法(TUNEL)检测心肌凋亡指数及梗死面积,比色法检测天冬氨酸蛋白水解酶(Caspase 3)及Caspase 8活性,Western-blot法检测Bax及Bcl-2表达,同时RTPCR法检测Fas及Fas-L mRNA表达。结果与假手术组比较,AMI组及NC组左室射血分数(LVEF)及左室长轴缩短分数(FS)升高,左室舒张末期内径(LVDd)及左室收缩末期内径(LVDs)降低,心肌凋亡指数提高,心肌梗死面积增大,Caspase 3及Caspase 8活性上升,Bax蛋白表达量上调,Bcl-2蛋白表达量下调,Fas及Fas-L mRNA水平上升,差异具有统计学意义(P0.01)。与AMI组及NC组比较,miR-126组能扭转此变化,差异具有统计学意义(P0.01)。结论 miR-126能显著抑制AMI大鼠心肌细胞凋亡,与调节细胞凋亡相关蛋白表达有关。

Effect of miR-126 on apoptosis of myocardial cells in rats with acute myocardial infarction

Objective To explore effect of miR-126 on apoptosis of myocardial cells in rats with acute myocardial infarction (AMI). Methods AMI model was established by ligation of left anterior descending branch of coronary artery. The survivors were randomly divided into 3 groups:AMI group, NC group and miR-126 group. the NC group and miR-126 group were injection of lentiviral transfection of miR-126 mimics NC and miR-126 mimics. The sham operation group was left anterior descending coronary artery without ligation. The rats'' cardiac function was recorded. Apoptosis index and infarct size of myocardium was detected by TCC method and in situ end method (TUNEL), respectively. The activity of cysteinyl aspartate specific proteinase 3 (Caspase 3) and Caspase 8 were determinated by colorimetry. The expression of Bcl-2, Bax was assayed by Western-blot. The expression of Fas and Fas-L mRNA was detected by RT-PCR. Results Compared with sham operation group, left ventricular ejection fraction (LVEF) and left ventricular long axis shortening fraction (FS) was increased, left ventricular end diastolic diameter (LVDd) and left ventricular end systolic diameter (LVDs) was decreased, apoptosis index was increased, myocardial infarction area increased, the activity of Caspase 3 and Caspase 8 was increased, the expression of Bax protein was upregulated, the expression of Bcl-2 protein was downregulated, the expression of Fas and Fas-L mRNA was increased in AMI and NC group, the difference was statistically significant (P<0.01). Compared with AMI and NC group, miR-126 could reverse the change, the difference was statistically significant (P<0.01). Conclusions miR-126 could inhibit apoptosis of myocardial cells in rats with AMI, which related to regulation of expression of cell apoptotic related protein.