甘精胰岛素对糖尿病大鼠心肌纤维化及超微结构的影响

Effects of insulin glargine on myocardial fibrosis and ultrastructure of myocardium in diabetic rats

目的探讨甘精胰岛素对糖尿病大鼠心肌的保护作用。方法将雄性Wistar大鼠随机分为正常对照组(NC组)、糖尿病组(DM组)和胰岛素治疗组(DI组),DI组给予甘精胰岛素经腹部皮下注射,治疗5周后称重并计算心脏体重比(H/B);免疫组化法测定各组心肌转化生长因子β1(TGF-β1)、Ⅲ型胶原蛋白(collagenⅢ)的表达;透射电镜观察心肌超微结构。结果①与NC组比较,DM组和DI组的H/B、TGF-β1、collagenⅢ均明显增高(P<0.05);与DM组比较,DI组的H/B、TGF-β1、collagenⅢ均下降(P<0.05)。②心肌超微结构:DM组肌原纤维排列紊乱,线粒体增多,常有肿胀变性;而DI组病变轻微。结论甘精胰岛素降低了心肌组织中TGF-β1及collagenⅢ的表达,延缓了糖尿病大鼠心肌纤维化的进程,改善了心肌超微结构。

Objective To investigate the protective effect of insulin glargine in myocardium of diabetic rats. Methods Male Wistar rats were randomly divided into normal control group （NC）, diabetes mellitus group （DM）, diabetes with insulin glargine [1. 5 U/（kg · d）] treatment group （DI）. After 6 weeks, we weighed rats and calculated the heart body weight ratio （H/B）, Immunohistochemical technique was used to estimate the expression of transforming growth factor beta 1 （TGF-β1） and the type-Ⅲ collagen （collagen Ⅲ ）. Myocardial pathologic changes were observed under transmission electronic microscope. Results （1） The levels of H/B and the expression of TGF-β1 and collagen Ⅲ of DM group and DI group were significantly higher than those in NC group （P〈0.05） ; the levels of H/B and the expression of TGF-β1 and collagen Ⅲ of DI group were lower than those in DM group （p〈0.05）. （2） Myocardial ultrastructure： In DM group, myofibrils were arranged disorderly, mitochondria increased, with swelling and degeneration, while the changes of myocardial ultrastructure were obviously lightened after treatment with insulin glargine. Conclusion Insulin glargine may partly suppress the increased expression of TGF-β1 and collagen Ⅲ in myocardial of diabetic rats, and it may decrease significantly the myocardial injury of diabetic rats.