MicroRNA-126-5p在阿霉素所致损伤心肌中的表达及作用

Role of microRNA-126-5p in myocardial injury induced by doxorubicin

目的:探讨微小RNA-126-5p(microRNA-126-5p)在阿霉素诱导的小鼠损伤心肌中的表达及在心肌细胞损伤中的作用。方法:采用BALB/c小鼠腹腔注射阿霉素的方法制备小鼠急、慢性阿霉素心肌损伤模型,苏木精-伊红(HE)染色检测小鼠心肌形态学改变,乳酸脱氢酶(LDH)试剂盒测定小鼠血清中的LDH活性,应用PowerLab数据采集分析系统检测小鼠心肌损伤情况。采用real-time PCR法检测阿霉素刺激大鼠心肌细胞株H9c2后micro RNA-126-5p的表达情况;转染microRNA-126-5p模拟物或抑制物,检测microRNA-126-5p模拟物及抑制物对阿霉素刺激后H9c2细胞microRNA-12-5p表达水平、LDH释放及caspase-3活化情况的影响。结果:在小鼠急、慢性阿霉素心肌损伤模型中,HE染色发现小鼠心肌纤维排列紊乱,肌原纤维溶解,局部有炎症细胞浸润;血清LDH释放增多(P<0.05);左心室等容舒张期压力下降最大速率(-dp/dtmax)及左心室等容收缩期压力上升最大速率(+dp/dtmax)下降;real-time PCR检测发现小鼠心肌中microRNA-126-5p的表达显著上调。阿霉素所致H9c2心肌细胞损伤中也伴有microRNA-126-5p表达明显上调;进一步采用micro RNA-126-5p模拟物与抑制物转染H9c2细胞,发现与单纯阿霉素处理组相比,microRNA-126-5p模拟物组LDH的释放增加,caspase-3活性升高,而microRNA-126-5p抑制物组结果则与之相反。结论:阿霉素可诱导小鼠心肌细胞microRNA-126-5p的表达明显升高,进而降低心肌细胞活性,促进心肌细胞凋亡,发挥促心肌损伤作用。

AIM:To observe the expression of microRNA-126-5p during myocardial injury and its role in myocardial cell injury induced by adriamycin(also called doxorubicin,DOX).METHODS:The BALB/c mouse model of DOX-induced acute and chronic myocardial injury was established via intraperitoneal injection of DOX.HE staining was applied to observe the morphological changes of myocardial tissues.Lactate dehydrogenase(LDH)in serum was detected and PowerLab system was used to detect the influence of DOX on the changes of±dp/dtmax.The expression of microRNA-126-5p in injured myocardial tissues and the H9c2 cells exposed to DOX was detected by real-time PCR.Gain-and loss-of-function experiments were conducted to detect the role of microRNA-126-5p in H9c2 cells treated with DOX on LDH release and caspase-3 activation.RESULTS:In acute and chronic DOX myocardial damage models in mice,HE staining showed disarranged myocardial fibers,dissolved myofibril and inflammatory cell infiltration.Higher serum LDH level and lower±dp/dtmax in DOX-treated mice than those in normal mice were found.Compared with the normal mice,the expression level of microRNA-126-5p was significant increased in the myocardium with DOX-induced injury.Similarly,the expression level of microRNA-126-5p was significant increased in the H9c2 cells treated with DOX.In addition,over-expression of microRNA-126-5p decreased cell viability and promoted apoptosis,while microRNA-126-5p ablation promoted the viability and inhibited the apoptosis of H9c2 cells.CONCLUSION:The microRNA-126-5p expression is up-regulated in myocardial injury induced by DOX,and microRNA-126-5p inhibits cell viability and promotes apoptosis induced by DOX.