miR-499-5p干预对心肌梗死大鼠心肌细胞凋亡的影响
Effects of miR-499-5p intervention on myocardial cell apoptosis in rats with myocardial infarction

目的:探究miR-499-5p在大鼠心肌梗死后心肌细胞凋亡中的作用和相关机制。方法:80只大鼠随机分为假手术组、心肌梗死组(AMI组)、AMI+miR-499-5p mimics组(干预组)、AMI+scramble-NC组(阴性对照组)。TUNEL法检测心肌细胞凋亡; qRT-PCR检测Sox6 mRNA表达; Western blot分析Sox6、Bax、Bcl-xl蛋白表达; 超声心动图评估心功能; 荧光素酶报告实验检测miR-499-5p是否靶向调控Sox6 3'非编码区。结果:与假手术组比较,AMI组心肌细胞凋亡率增高,Sox6 mRNA和蛋白及Bax蛋白表达增高,Bcl-xl蛋白表达降低,EF值和FS值均降低(P均<0.05); 与阴性对照组、AMI组比较,干预组心肌细胞凋亡率、Sox6 mRNA和蛋白及Bax蛋白表达降低,Bcl-xl蛋白表达增高,EF、FS值增加(P均<0.05)。荧光素酶报告实验提示miR-499-5p 特异性调控Sox6 3'末端非编码序列。结论:miR-499-5p可能通过靶向抑制Sox6的表达来抑制心肌细胞凋亡,最终改善心功能。
Aim: To investigate the role of miR-499-5p in cardiomyocyte apoptosis after myocardial infarction in rats and explore its molecular mechanism.Methods: The rats were randomly allocated into sham operation group, AMI group, intervention group(AMI+intravenous injection of miR-499-5p mimics after pulse ligation),and negative control group(AMI+intravenous injection of negative control sequence).Cardiomyocyte apoptosis was detected by TUNEL staining. Sox6 mRNA was detected by qRT-PCR; the expressions of Sox6, Bax, Bcl-xl protein were detected by Western blot; heart function was detected by Vevo 2100. Luciferase reporter assay was used to detect whether miR-499-5p targeted Sox6 3' non-coding region.Results: Compared with the sham operation group,the apoptosis rate, Sox6 and Bax expression increased,while Bcl-xl expression,the values of EF and FS decreased in AMI group(P<0.05).Compared with the negative control group and AMI group, the apoptosis rate,Sox6,Bax protein decreased,while Bcl-xl expression and the values of EF and FS increased.Luciferase reporter assay showed that miR-499-5p specifically regulated the 3' non-coding region of Sox6.Conclusion:miR-499-5p may inhibit cardiomyocyte apoptosis by targeted inhibition of Sox6 expression, and ultimately improve cardiac function