急性心肌梗死大鼠中微小RNA-221的表达及相关机制

Expression of microRNA-221 and its related mechanisms in rats with acute myocardial infarction

目的探讨急性心肌梗死(AMI)大鼠中微小RNA(miRNA,miR)-221的表达及相关机制。方法通过冠状动脉左前降支结扎大鼠来建立AMI模型,将构建成功的36只AMI大鼠随机分为AMI组、对照组及抑制组,另外设立假手术组采用冠状动脉左前降支穿线不结扎,每组12只。其中抑制组及对照组分别采用心肌组织局部注射慢病毒转染的miR-221 inhibitor及miR-221阴性对照(NC),AMI组和假手术组每天给予等量生理盐水。测定每组大鼠miR-221表达、心肌凋亡指数(AI)、天冬氨酸蛋白水解酶(Caspase)-3及Caspase-9活性、B淋巴细胞瘤-2(bcl-2)、bcl-2相关X蛋白(bax)、细胞周期蛋白依赖性蛋白激酶抑制剂p27、p57蛋白表达及人第10号染色体缺失的磷酸酶及张力蛋白同源的基因(PTEN)/蛋白激酶B(Akt)信号通路激活情况,采用t检验分析组间差异。结果与AMI组及对照组比较,抑制组中AI(t=5.874,P<0.01)及Caspase-3(t=6.219,P<0.01)及Caspase-9(t=5.942,P<0.01)活性显著降低,差异有统计学意义,bax(t=8.512,P<0.01)、p27(t=5.878,P<0.01)、p57(t=11.244,P<0.01)及PTEN(t=6.063,P<0.01)表达量下调,差异有统计学意义,bcl-2(t=5.971,P<0.01)及p-Akt(t=9.140,P<0.01)表达量上调,差异有统计学意义。结论miR-221低表达能显著抑制AMI大鼠心肌损伤,与调控PTEN/Akt信号通路有关。

Objective To explore expression of microRNA (miRNA, miR)-221 and its related mechanisms in rats with acute myocardial infarction (AMI). Methods AMI model was established by ligation of left anterior descending branch of coronary artery. Thirty-six AMI rats successfully established were randomly divided into AMI group, control group and inhibition group with 12 rats in each group. The control group and inhibition group was injected with green fluorescent protein (GFP) lentiviral vector miR-221 negative control (NC) and miR-221 inhibitor by local injection of myocardial tissue transfection, respectively. AMI group and sham operation group were given normal saline. The expression of miR-221, Apoptosis index (AI) in myocardium, The activity of aspartic proteinase (Caspase)-3 and Caspase-9, the expression of B lymphocytes -2 (bcl-2), bcl-2 associated X protein (bax), cyclin dependent protein kinase phosphatase signaling pathway activation was detected. Results Compared with AMI group and control group, AI (t=5.874, P<0.01), the activity of Caspase-3 (t=6.219, P<0.01), Caspase-9 (t=5.942, P<0.01) and the expression of bax (t=8.512, P<0.01), p27 (t=5.878, P<0.01), p57 (t=11.244, P<0.01), phosphatase and tensin homolog deleted on chromosome ten (PTEN, t=6.063, P<0.01) was decreased, the expression of bcl-2 (t=5.971, P<0.01) and p-Akt (t=9.140, P<0.01) was increased in inhibition group (P<0.01). Conclusion Down-expression of miR-221 could significantly inhibit AMI rat’ myocardial injury, which related to regulation of PTEN/Akt signal pathway.