2型糖尿病大鼠早期血清cTnI水平与心功能的变化

目的:研究2型糖尿病大鼠早期血清心肌肌钙蛋白I(cTnI)的水平及心功能变化,探讨早期2型糖尿病大鼠血清cTnI水平与糖尿病心肌损伤发生发展之间的关系,明确cTnI在糖尿病心肌病发生发展中的作用。方法:通过高脂饮食联合链脲佐菌素建立2型糖尿病大鼠模型,实验将大鼠分为正常对照组、糖尿病2周模型组及4周模型组,超声心动图检测心功能相关指标,血清检测空腹血糖(FBG)、总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白(HDL-C)、低密度脂蛋白(LDL-C)、空腹胰岛素(FINS)及cTnI水平,HE染色法观察心肌病理结构变化,Western blot法检测心肌cTnI蛋白表达变化,通过上述指标变化分析2型糖尿病大鼠早期血清cTnI与大鼠心功能改变之间的关系。结果:与正常组比较,2型糖尿病大鼠TC、TG、LDL-C水平显著升高,HDL-C水平显著降低;糖尿病大鼠4周模型组与2周模型组相比较,TC、TG、LDL-C水平升高更明显,HDL-C水平降低更显著(P0.01);显微镜下糖尿病组大鼠心肌可见局灶性心肌细胞变性、坏死;糖尿病组大鼠相对于正常对照组血清及心肌cTnI表达显著增加(P0.01),且4周模型组比2周模型组增加更明显。结论:糖尿病大鼠早期即出现cTnI水平升高和心功能改变,有望为糖尿病心肌病的早期诊断和治疗提供理论依据。

Changes of heart function and serum cardiac troponin I in early type 2 diabetic rats

AIM: To observe the changes of heart function and the expression of serum cardiac troponin I(cTnI) in early type 2 diabetic rats, and to explore the role of cTnI in the development of type 2 diabetes and early diabetic cardiomyopathy.METHODS: The type 2 diabetes rat model was established by an injection of streptozotocin after high fat diet(5 weeks). The rats were randomly divided into control group, model group of 2 weeks, and model group of 4 weeks. M-mode echocardiography was performed for echocardiographic measurements. Fasting blood glucose(FBG), total cholesterol(TC), triglyceride(TG), high density lipoprotein-cholesterol(HDL-C), low density lipoprotein- cholesterol(LDL-C), fasting insulin(FINS) and cTnI levels were tested. HE staining was used to observe the pathological changes of myocardial structures. The alteration of cTnI in myocardium was determined by Western blot.RESULTS: Compared with normal group, the levels of TC, TG and LDL-C in type 2 diabetic rats were significantly increased, HDL-C levels were significantly reduced. Cardiac histological analysis revealed that type 2 diabetes induced cardiomyocytes degeneration and necrosis. The expression of cTnI increased significantly in diabetic groups compared to control group, and that in model group of 4 weeks increased far more than that in model group of 2 weeks(P<0.05).CONCLUSION: The increased level of cTnI and the change of the heart function may be associated with the development diabetic cardiomyopathy. These changes are valuable for the early clinical diagnosis of myocardial injury in diabetic cardiomyopathy.