MiR-145在低氧诱导的心肌细胞中的表达及其作用研究

Expression and Effect of miR-145 in the Apoptotic Neonatal Rat Cardiomyo-cytes Induced by Hypoxia

目的:探讨Mi R-145在低氧诱导的心肌细胞凋亡模型中的表达及其意义。方法:在正常和低氧条件下,采用RT-qPCR检测乳大鼠原代心肌细胞mi R-145的表达,进一步采用mi R-145抑制剂和拟似物处理心肌细胞,将细胞置于37℃密闭的缺氧盒中(95%N2和5%CO2)培养,采用Caspase-3活性分析和TUNEL检测心肌细胞凋亡情况。通过结扎SD大鼠冠状动脉左前降支(LAD)建立心肌缺血再灌注(I/R)模型,了解mi R-145在缺血再灌注损伤中的作用。结果:mi R-145过表达可抑制缺氧诱导的心肌细胞凋亡。转染mi R-145抑制剂后,细胞对缺氧更敏感。缺血0.5h、1h和3h的心肌组织中mi R-145的表达明显低于周围非缺血心肌组织。缺氧3h、6h、12h时mi R-145水平明显下调。在缺血再灌注损伤模型中,mimic组Mi R-145表达明显高于对照组,而凋亡细胞(%)和梗死面积危险区(%)明显低于对照组。结论:Mi R-145可以抑制缺氧诱导的心肌细胞凋亡,减小缺血再灌注损伤导致的心肌梗死面积。

Objective:To investigate the expression and clinical significance of microRNA-145(miR-145)in the apoptosis model of cardiomyocytes induced by hypoxia.Methods:Under normal and hypoxic conditions,the expression of miR-145 in neonatal rat cardiomyocytes was detected by RT-qPCR.miR-145 inhibitor and mimic were transfected into the primary neonatal rat cardiomyocytes.The transfected cardiomyocytes were cultured in closed anoxic box(95%N 2 and 5%CO2)at 37℃.Ischemiareperfusion(I/R)of animal model was established by left anterior descending coronary artery(LAD).Results:Overexpression of miR-145 can inhibit hypoxia-induced cardiomyocyte apoptosis.The cells were more sensitive to hypoxia after transfection with miR-145 inhibitor.The levels of miR-145 in ischemic myocardium tissue were significantly lower than the surrounding non-ischemic myocardium tissue at 0.5 h,1 h and 3 h after ischemia.The levels of miR-145 were significantly down-regulated at 3 h,6 h,and 12 h of hypoxia.MiR-145 in mimic group was significantly higher than that of the control group,while apoptotic cells(%)and infarct size/area at risk(%)were significantly lower than that of the control group.Conclusions:Mir-145 can inhibit hypoxia-induced myocardial cell apoptosis and reduce the myocardial infarction area caused by ischemia reperfusion injury.