miRNA-21对2型糖尿病心肌病大鼠心肌纤维化的影响

Effect of miRNA-21 on myocardial fibrosis in rats with type 2 diabetic cardiomyopathy

目的探究miRNA-21对2型糖尿病心肌病大鼠心肌纤维化的影响。方法将32只雄性SD大鼠随机分为四组:对照组、DCM组、DCM+干扰miRNA-21组、DCM+干扰对照组,每组8只。给予DCM组、DCM+干扰miRNA-21组、DCM+干扰对照组大鼠高糖高脂饮食4周后,腹腔注射25 mg/kg链脲佐菌素(STZ),每2周对各组大鼠进行体重、空腹血糖测量,第8周时经尾静脉对DCM+干扰miRNA-21组、DCM+干扰对照组进行慢病毒转染,第12周时所有试验动物处死,进行指标检测;qRT-PCR检测大鼠心肌组织中miRNA-21的表达;HE检测心肌细胞病理学改变;Masson检测心肌组织中胶原纤维的表达;免疫组织化学染色法观察α-SMA的表达。结果与对照组相比,DCM组大鼠出现体重先增长后下降的趋势,其空腹血糖≥11.1 mmol/L,差异有统计学意义(P<0.05);在转染慢病毒后(注射STZ第8周),与DCM+干扰对照组相比,DCM+干扰miRNA-21组大鼠体重有所增加,空腹血糖水平下降,差异有统计学意义(P<0.05)。与对照组相比,DCM组、DCM+干扰miRNA-21组、DCM+干扰对照组大鼠心肌组织中miRNA-21表达量增加;与DCM+干扰对照组比较,DCM+干扰miRNA-21组心肌中miRNA-21表达量下降,差异有统计学意义(P<0.05);与对照组相比,DCM组、DCM+干扰miRNA-21组、DCM+干扰对照组大鼠出现心肌纤维断裂,周围有炎细胞浸润,且心肌中胶原纤维表达量增加;与DCM+干扰对照组比较,DCM+干扰miRNA-21组改善了心肌纤维的损伤,并降低了胶原纤维表达量,差异有统计学意义(P<0.05);与对照组相比,DCM组、DCM+干扰miRNA-21组、DCM+干扰对照组大鼠心肌组织中α-SMA表达量升高;与DCM+干扰对照组比较,DCM+干扰miRNA-21组的心肌组织中α-SMA表达量下降,差异有统计学意义(P<0.05)。结论miRNA-21参与了DCM的发展过程,抑制miRNA-21的表达可以改善DCM心肌纤维化。

Objective To investigate the effect of miRNA-21 on myocardial fibrosis in type 2 diabetic cardiomyopathy rats.Methods Thirty-two male SD rats were randomly divided into four groups:control group,DCM group,DCM+interference miRNA-21 group,DCM+interference control group,8 rats in each group.Rats in the DCM group,DCM+interference miRNA-21 group,and DCM+interference control group were given a high-sugar diet for 4 weeks and intraperitoneally injected with 25 mg/kg streptozotocin(STZ).Lentiviral transfection was performed in DCM+interference miRNA-21 group and DCM+interference control group via tail vein on the 8th day of STZ injection.Body weight and fasting blood glucose were measured in each group of rats every 2 weeks after STZ injection.The rats were sacrificed on the 12th day of STZ injection,the expression of miRNA-21 in the myocardial tissue of rats in each group was detected by qRT-PCR.The morphological changes of myocardial structure;the expression of collagen fibers in the myocardial tissue of rats in each group were observed by HE and Masson pathological staining methods;The expression ofα-SMA in the myocardial tissue of rats in each group was further observed by immunohistochemical staining.Results Compared with the control group,the rats in the DCM group showed a trend of weight gain first and then decrease,and their fasting blood glucose was≥11.1 mmol/L,and the difference was statistically significant(P<0.05).After transfection with lentivirus(the 8th week of STZ injection),the rats in the DCM+interference miRNA-21 group had increased body weight and decreased fasting blood glucose level compared with the DCM+interference control group,and the difference was statistically significant(P<0.05).Compared with the control group,miRNA-21 expression in the myocardial tissue of rats in the DCM,DCM+interference miRNA-21,and DCM+interference control groups increased,compared with the DCM+interference control group,miRNA-21 expression in the myocardium of rats in the DCM+interference miRNA-21 group decreased,and the difference was statistically significant(P<0.05).Compared with the control group,rats in the DCM,DCM+interference miRNA-21,and DCM+interference control groups showed myocardial fiber rupture,surrounding inflammatory cell infiltration,and increased collagen fiber expression in the myocardium;compared with the DCM+interference control group,the DCM+interference miRNA-21 group improved the damage of myocardial fibers,and decreased collagen fiber expression,and the difference was statistically significant(P<0.05).Compared with the control group,rats in the DCM,DCM+interference miRNA-21,and DCM+interference control groups had increasedα-SMA expression in the myocardial tissue;compared with the DCM+interference control group,The difference was statistically significant(P<0.05).Conclusion miRNA-21 is involved in the development of diabetic cardiomyopathy,and inhibiting its expression can improve the degree of myocardial injury and fibrosis in DCM.