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目的观察内质网应激(ERS)分子半胱氨酸天冬氨酸蛋白酶12(Caspase 12)在糖尿病心肌病(DCM)大鼠的表达及葛根素的干预作用,探讨ERS在DCM中的作用和机制。方法采用腹腔注射链脲佐菌素制备糖尿病大鼠模型。40只Wistar大鼠分为正常对照组(C组)、高脂高糖组(H组)、糖尿病模型组(M组)及葛根素组80mg·kg-1·d-1给药5周(T组),每组10只,分批处死。15、20周龄大鼠取血测空腹血糖、胰岛素及计算胰岛素抵抗指数;取心肌组织检测肌酸激酶、乳酸脱氢酶水平,并行苏木精-伊红染色观察形态学变化。琼脂糖凝胶电泳法检测DNA梯形条带,反转录聚合酶链反应(RT-PCR)测定Caspase 12 mRNA的表达。结果 H、M组的空腹血糖、胰岛素和胰岛素抵抗指数都显著高于C组(P均<0.01),且M组显著高于H组(P<0.01)。在葛根素给药5周后,T组空腹血糖及胰岛素抵抗指数均呈显著下降(P均<0.01)。M组心肌纤维肥大、走行较为紊乱,出现核固缩、裂解及丢失现象,心肌细胞变性、坏死,横纹肌消失;T组心肌纤维轻度肥大,微血管管壁、管腔均正常。M组和T组均出现了DNA梯形条带,T组较M组条带不明显。M组Caspase12mRNA表达较C组、T组均显著性升高(P均<0.05)。结论 DCM可能通过ERS而活化Caspase12来触发心肌细胞凋亡。葛根素能通过减轻ERS抑制心肌细胞凋亡,对DCM心肌有保护作用。
Objective To investigate the expression of endoplasmic reticulum stress (RSS) Caspase 12 in diabetic cardiomyopathy (DCM) rats and the effect of puerarin on ERS in DCM And mechanism. Methods Diabetic rats were induced by intraperitoneal injection of streptozotocin. 40 Wistar rats were divided into normal control group (C group), high fat group (H group), diabetes model group (M group) and puerarin group 80 mg · kg -1 · d -1 for 5 weeks T group), each group of 10, died in batches. 15, 20 weeks old rats blood was taken to measure fasting blood glucose, insulin and calculate the index of insulin resistance; creatine kinase and lactate dehydrogenase levels were measured in myocardium, and morphological changes were observed by hematoxylin-eosin staining. DNA ladder was detected by agarose gel electrophoresis and the expression of Caspase 12 mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR). Results The fasting blood glucose, insulin and insulin resistance index of H and M groups were significantly higher than those of C group (P <0.01), and M group was significantly higher than that of H group (P <0.01). After 5 weeks of puerarin administration, the fasting blood glucose and insulin resistance index of T group were significantly decreased (all P <0.01). In M group, the cardiac muscle fibers were hypertrophy and walked in a disorderly manner. Nuclear pyknosis, lysis and loss occurred. Myocardial cell degeneration, necrosis and rhabdomyolysis disappeared. The myocardial fibers of group T were mildly hypertrophy and the vascular wall and lumen were normal. DNA trapezoidal bands appeared in both M group and T group, and the bands in T group were not obvious than those in M group. Caspase12 mRNA expression in M group was significantly higher than that in C group and T group (all P <0.05). Conclusion DCM may activate Caspase12 through ERS to trigger cardiomyocyte apoptosis. Puerarin can protect the myocardium of DCM by reducing the apoptosis of cardiomyocytes induced by ERS.