半胱氨酸天冬氨酸蛋白酶12在糖尿病心肌病大鼠心肌中的表达及葛根素的干预研究

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。

Research on the expression of Caspase 12 in rats with diabetic cardiomyopathy and the intervention of puerarin

Objective To observe the expression of Caspase 12 and the intervention of puerarin in rats with diabetic cardiomyopathy (DCM), and to explore the possible effects of endoplasmic reticulum stress (ERS) on the pathogenesis of DCM. Methods Diabetic models were established by intraperitoneal injection of 35 mg / kg streptozotocin (STZ) in rats. Forty Wistar rats were randomly divided into four groups, 10 in each: normal control group (C group), high fat and sugar group (H group), diabetic model group (M group) and puerarin treatment group (T group, intraperitoneal injection of 80 mg·kg-1·d-1 puerarin for 5 weeks), and killed in batches. The myocardial tissue were obtained and dyed with hematoxylin-eosin staining to observe morphological changes. The levels of creatine kinase and lactate dehydrogenase were detected, and DNA ladder by agarose gel electrophoresis. Reverse- transcription polymerase chain reaction (RT-PCR) was used to determine the expression of Caspase 12 mRNA. Fasting blood glucose, fasting insulin and insulin resistance index were measured in the 15 and 20-week-old rats. Results The fasting blood glucose, serum insulin and insulin resistance index in the H, M groups were significantly higher than the C group (all P < 0.01). After treating with puerarin for five weeks, the fasting blood glucose and serum insulin resistance index in the T group were all obviously decreased (all P < 0.01). In the M Group, myocardial fiber hypertrophy and disorder, karyopyknosis and karyorrhexis were observed. Myocardial cells degenerated and necrosed, and striated muscle disappeared. However, in the T group, the myocardial fiber hypertrophy were mild, and capillary walls and lumens were normal. Agarose gel electrophoresis showed the DNA ladder in both the M and T groups, especially obvious in the M group. Caspase 12 mRNA expression in the M group was significantly higher than the C and T groups (all P < 0.05). Conclusions ERS, which can activate the Caspase 12, plays an important role in the pathogenesis of DCM. Puerarin may reduce ERS and protect myocardial cells in the rats with DCM.