Objective To investigate the effect of benazepril (BZ) on the expression of TGF-β1 and Bax on diabetic myocardium and myocardial hypertrophy. Methods Diabetic animal models were induced by injecting streptozotocin. Model rats were divided into diabetes and BZ groups, control group was also established. BZ was given to treatment group at dose of 10 mg/kg each day by gavage. At 8 weeks, heart mass indexes (HMI) and left ventricular myocardium mass indexes (LVMI) were measured. The expressions of TGF-β1 and Bax in cardiomyocyte were detected and myocardium was studied by electronic microscope. Results Compared with control group, HMI and LVMI were significantly increased in diabetes group ( P ＜ 0. 05 ). The expression of TGF-β1 and Bax were strengthened in diabetic myocardium. Electron microscopic morphometry of heart samples revealed typical diabetic alterations consisting in a focal loss, disorganization of myofihril, mitochondria swelling, collagen proliferation in extracellular matrix. After treatment with BZ for 8 weeks, HMI and LVMI were decreased ( P ＜ 0. 01 ). The expression of TGF-β1 and Bax were weakened and myocardial ultrastructure was better than that of diabetes group. Conclusions TGF-β1 can induce myocardial apoptosis by stimulating the expression of Bax and promote diabetic cardiac hypertrophy, BZ can improve the cardiac function partly due to its effects of downregulating the expression of TGF-β1 and Bax.%目的 探讨贝那普利(BZ)对糖尿病(DM)大鼠心肌转化生长因子β1(TGF-β1)和Bax的表达及心肌肥厚指标的影响.方法 SD大鼠腹腔注射链脲佐菌素(STZ)制备DM模型.实验分为正常对照组(CON)、DM组和BZ治疗组(BZ).治疗组每日灌胃给予贝那普利(10 mg·kg-1·d-1).8 w后测定心脏质量指数(HMI)、左心室质量指数(LVMI),并取左心室心肌免疫组化法检测TGF-β1和 Bax在心肌组织中的表达,透射电镜观察心肌组织超微结构变化.结果 与CON组相比,DM组大鼠HMI、LVMI明显升高;心肌TGF-β1和 Bax蛋白表达显著增强(P＜0.05,P＜0.01);电镜发现DM心肌细胞肿胀、肌丝稀疏,线粒体变性肿胀,间质胶原增生及微血管基底膜增厚.与DM组相比,BZ干预后,HMI、LVMI明显降低(P＜0.01);心肌TGF-β1和 Bax蛋白表达减弱(P＜0.01);心肌超微结构改变减轻.结论 TGF-β1 可能通过刺激促凋亡因子Bax表达诱导心肌细胞凋亡,促进DM心肌肥厚.BZ能在一定程度上抑制TGF-β1和Bax的表达从而延缓DM心肌病理进程.
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