中文摘要：

目的：探讨neuregulin-1（NRG-1）在糖尿病大鼠心肌组织中的表达。方法：45只雄性SD大鼠随机分为4周、8周和12周糖尿病组（4th、8th和12th DM组）,4周、8周和12周对照组（4th、8th和12th C组）。腹腔注射链脲佐菌素诱导糖尿病模型。在诱导糖尿病后第4、8和12周用超声诊断仪评估大鼠心功能,计算心肌胶原容积分数（CVF）,免疫组化观察NRG-1在心肌的表达部位,RT-PCR和Western blotting检测NRG-1 mRNA及蛋白的表达水平。结果：4th DM组大鼠心功能指标、心肌CVF、NRG-1 mRNA及蛋白的表达与4thC组相比,差异无统计学意义（P〉0.05）;与8th C组相比,8th DM组左室收缩末内径（LVESD）和心肌CVF均增高,但左室短轴缩短率（LVFS）、左室射血分数（LVEF）、心肌NRG-1 mRNA及蛋白的表达仍未见明显改变（P〉0.05）。与12th C组比较,12th DM组LVESD和心肌CVF均显著增高,而LVFS和LVEF显著降低（均P〈0.01）。12th DM组心肌NRG-1 mRNA及蛋白的表达较同期对照组显著下调（0.073±0.008 vs 0.156±0.010,0.171±0.054 vs 0.324±0.039,均P〈0.01）。结论：NRG-1在糖尿病大鼠心肌组织中的表达显著下调,这可能参与了糖尿病心肌病的发生和发展。

英文摘要：

AIM： To explore the expression of neuregulin-1（NRG-1） at mRNA and protein levels in the myocardial tissues of diabetic rats.METHODS： Forty-five male SD rats were randomly divided into diabetic groups of the 4th,8th and 12th weeks（4th,8th and 12th DM groups） and control groups of the 4th,8th and 12th weeks（4th,8th and 12th C groups）.Diabetic rat model was induced by a single intraperitoneal injection of streptozotocin（STZ） at a dose of 55 mg/kg.Echocardiographic parameters,collagen volume fraction（CVF）,and the mRNA and protein expression levels of NRG-1 were observed at the 4th,8th and 12th weeks after STZ injection.RESULTS： No statistical significant difference of the echocardiographic parameters,CVF,and the mRNA and protein expression levels of NRG-1 between 4th DM group and 4th C group was observed.Compared with 8th C group,left ventricular systolic dimension（LVESD） and CVF significantly increased in 8th DM group.No statistical significance of left ventricular fractional shortening（LVFS）,left ventricular ejection fraction（LVEF）,and the mRNA and protein expression levels of NRG-1 between 8th DM group and 8th C group was found.Compared with 12th C group,LVESD and CVF increased,while LVFS and LVEF significantly decreased in 12th DM group.The mRNA and protein expression levels of NRG-1 in 12th DM group were much lower than those in 12th C group（0.073±0.008 vs 0.156±0.010 and 0.171±0.054 vs 0.324±0.039,both P0.01）.CONCLUSION： The mRNA and protein expression levels of NRG-1 in the myocardial tissues of diabetic rats are down-regulated,which may play some roles in the progression of diabetic cardiomyopathy.