Apelin-13对糖尿病大鼠心肌代谢的影响

摘要

目的 观察外源性给予Apelin-13对糖尿病大鼠心肌细胞代谢的影响. 方法 40只雄性Wister大鼠随机分成对照组8只,实验组32只.实验组通过高糖高脂饮食联合小剂量腹腔注射链脲佐菌素(STZ)构建2型糖尿病大鼠模型.造模成功的糖尿病大鼠随机分成糖尿病模型组14只,Apelin-13给药组14只.给药组给予Apelin-13 0.1 μmol·kg-1·d-1腹腔注射,对照组和糖尿病模型组给予0.9％氯化钠溶液等体积腹腔注射,连续给药10周.10周末,测定大鼠空腹血糖后取材.酶联免疫吸附实验(ELISA)测定血清、心肌游离脂肪酸(FFA),免疫组化法比较各组大鼠心肌葡萄糖转运蛋白4(GLUT4)表达,实时荧光定量PCR检测心肌组织中过氧化物酶体增生物激活体-α(PPARα)、脂肪酸转运蛋白CD36、肉碱脂酰转移酶-1(CPT-1)等基因mRNA的表达. 结果 糖尿病模型组大鼠空腹血糖、血清FFA、心肌FFA水平升高(均P＜0.05),给予Apelin-13干预后,大鼠空腹血糖、心肌FFA水平较模型组下降,血清FFA水平下降不明显.糖尿病模型组和Apelin-13给药组心肌细胞PPARα、CD36、CPT-1 mRNA的基因相对表达水平较对照组升高(P＜0.05),经Apelin-13治疗后,给药组心肌细胞PPARα、CD36、CPT-1 mRNA的基因相对表达水平较糖尿病模型组下降(P＜0.05).心肌细胞GLUT4表达在糖尿病模型组(1.138±0.316)和Apelin-13给药组(4.631±1.832)较对照组(9.132±2.156)下降(F=65.507,P＜0.05),Apelin-13给药组较糖尿病模型组表达升高(P＜0.05). 结论 Apelin 13增加心肌葡萄糖转运蛋白4表达,增加游离脂肪酸的利用,同时能够有效地降低PPARα、CD36、CPT-1的表达,在一定程度上改善糖尿病大鼠心肌代谢.%Objectives To investigate the effects of Apelin 13 on myocardial metabolism in diabetic rats.Methods A total of 40 male Wister rats were randomly divided into normal control group (NC,n=8) and experimental group (n =32).Diabetic rats model were induced by high-sugar and high-fat diet combined with low-dose intraperitoneal injection of streptozotocin (STZ).The wellestablished 28 diabetic model rats were randomly divided into diabetic model group (DM,n=14) and apelin-13 treated group (n=14).In the Apelin-13 group,diabetic rats were administered Apelin-13 [0.1 μmol/(kg · d)]by intraperitoneal injection for 10 weeks,while the control group and diabetic model group were given an equal volume of 0.9％ NaCl.At the end of the 10th week,all rats were sacrificed after fasting glucose measurement.Levels of serum free fatty acids (FFA) and myocardial FFA were measured by ELISA.Expression of myocardial glucose transporter member 4 (GLUT4) were detected by immunohistochemistry.The mRNA expressions of myocardial PPARα,CD36 and CPT-1 were detected by real-time fluorescence quantitative PCR.Results Fasting blood glucose,serum FFA and myocardial FFA were significantly higher in DM group than in NC group (all P＜ 0.05).The level of plasma glucose and myocardial FFA were significant lower(P＞0.05) in Apelin-13 treated group than in DM group;but serum FFA was not significantly lower(P＜0.05).The mRNA expressions of PPARα,CD36,CPT-1 in cardiac myocyte were higher in DM group and Apelin-13 treated group than in control(P＜0.05),and lower in Apelin-13 treated group than in DM group(P＜ 0.05).The expression of myocardial GLUT4 was significantly lower in DM group(1.138±0.316)and in Apelin-13-treated group (4.631 ± 1.832) than in NC group(9.132 ± 2.156),(F=65.507,P＜ 0.05),and higher in Apelin-13-treated group than in DM group(P＜0.05).Conclusions Apelin-13 increases myocardial expression of GLUT4,improves utilization of FFA,and it can effectively reduce the expression of PPARα,CD36 and CPT-1.Therefore,it may play a vital role in the improvement of myocardial metabolism in diabetic rats.