Apelin-13对糖尿病大鼠肝脏及骨骼肌糖脂代谢基因水平表达的影响

Effects of Apelin-13 on expression levels of glucose and lipid metabolism-related genes in the liver and skeletal muscle of diabetic rats

目的观察外源性给予Apelin-13对糖尿病鼠肝脏及骨骼肌的葡萄糖及脂肪酸代谢基因表达的影响。方法40只雄性Wister大鼠，随机分成两组，对照组和实验组分别为8只及32只。实验组通过给予高糖、高脂饮食，联合低剂量腹腔注射链脲佐菌素（STZ）构建2型糖尿病大鼠模型。将造模成功的糖尿病大鼠随机分成糖尿病模型组和Apelin-13给药组各14只。给药组大鼠腹腔注射Apelin-13，0.1 μmol·kg－1·d﹣1，对照组及糖尿病模型组腹腔注射等体积0.9%NaCl溶液，持续给药10周。10周末，测定各组大鼠空腹血糖值后取材。实时荧光定量PCR检测肝脏组织中葡萄糖6磷酸酶（G6P）、磷酸烯醇式丙酮酸羧激酶（PEPCK）、过氧化物酶体增殖物激活体-α（PPARα）、脂酰辅酶A合成酶长链家族成员1（ACSL1）、肉毒碱棕櫚酰转移酶1（CPT1）的基因表达水平；骨骼肌中葡萄糖转运蛋白4（GLUT4）、过氧化物酶体增殖物激活体-α（PPARα）的基因的mRNA表达水平。结果糖尿病模型组肝脏PPARα mRNA表达水平低于对照组[（0.309±0.073）和（0.971±0.028），P〈0.05]，经外源性给予Apelin-13 10周干预后，PPARα mRNA表达水平[（0.663±0.085），P〈0.05）]较模型组有所升高，但低于对照组；糖尿病模型组肝脏ACSL1 mRNA表达水平低于对照组[（0.508±0.056）和（0.990±0.015），P〈0.05]经外源性给予Apelin-13 10周干预后，ACSL1 mRNA表达水平[（0.802±0.079），P〈0.05]较模型组有所升高，但低于对照组；糖尿病模型组肝脏CPT1 mRNA表达水平低于对照组[（0.398±0.118）和（0.987±0.015），P〈0.05]，经外源性给予Apelin-13 10周干预后，CPT1 mRNA表达水平[（0.752±0.097），P〈0.05]较模型组有所升高，但低于对照组；模型组大鼠G6P mRNA表达水平均高于对照组[（1.727±0.005）和（1.002±0.005），P〈0.05]，经外源性给予Apelin-13 10周干预后，G6P mRNA表达水平高于糖尿病模型组[（2.586±0.208），P〈0.05]；模型组大鼠PEPCK mRNA表达水平高于对照组[（1.309±0.130）和（0.993±0.010），P〈0.05]和，经外源性给予Apelin-13 10周干预后，PEPCK mRNA表达水平[（1.842±0.234），P〈0.05]均高于糖尿病模型组；糖尿病模型组大鼠骨骼肌PPARα mRNA表达水平低于对照组[（0.477±0.118）和（0.993±0.013），P〈0.05]，经外源性给予Apelin-13干预后，PPARα[（0.566±0.0780），P〉0.05]与糖尿病模型组比较差异无统计学意义，但低于对照组（P〈0.05）；糖尿病模型组大鼠骨骼肌GLUT4 mRNA表达水平低于对照组[（0.289±0.066）和（0.994±0.009）P〈0.05]，经外源性给予Apelin-13干预后，糖尿病模型组大鼠骨骼肌GLUT4 mRNA表达水平[（0.509±0.119），P〈0.05]较模型组有所升高，但低于对照组。结论Apelin-13增加肝脏PPARα、ACSL1、CPT1基因表达，在一定程度上改善2型糖尿病鼠肝脏脂肪酸氧化代谢。Apelin-13增加G6P、PEPCK基因表达，促进肝脏糖异生，可能参与2型糖尿病的发生发展。Apelin-13增加骨骼肌GLUT4基因表达，在一定程度上改善糖尿病大鼠骨骼肌糖代谢，可能参与骨骼肌氧化应激的调节。

Objective To investigate the effects of exogenous Apelin-13 on the expression of glucose and fatty acid metabolism-related genes in the liver and skeletal muscle of diabetic rats.MethodsForty male Wister rats were randomly divided into a control group （n=8） and an experimental group （n=32）. In the experimental group, a rat model of type 2 diabetes mellitus was established by a high-glucose and high-fat diet and intraperitoneal injection of streptozotocin （STZ）. The diabetic rats were randomized into a diabetic model group and an Apelin-13 treatment group with 14 rats in each group.Rats in the Apelin-13 treatment group were intraperitoneally injected with 0.1 μmol·kg·d-1 Apelin-13 for 10 weeks, while the control group and the diabetic model group were injected with an equal volume of 0.9% NaCl solution for 10 weeks.At the end of the 10 week treatment, fasting blood glucose values in each group were measured.Levels of mRNA expression of glucose-6-phosphate （G-6-P）, phosphoenolpyruvate carboxykinase （PEPCK）, peroxisome proliferator-activated receptor alpha （PPAR-α）, acy1-CoA synthetase long-chain family member1 （ACSL1）, and carnitine palmitoyltransferase1 （CPT1） in the liver and levels of mRNA expression of PPAR-α and glucose transporter type 4 （GLUT4） in skeletal muscle were detected by real-time fluorescence quantitative polymerase chain reaction （PCR）.ResultsLevels of mRNA expression of liver PPAR-α, liver ACSL1, liver CPT1, and GLUT4 in skeletal muscle were lower in the diabetic model group （0.309±0.073, 0.508±0.056, 0.389±0.118 and 0.289±0.066, respectively） than in the control group （0.971±0.028, 0.990±0.015, 0.987±0.015 and 0.994±0.009, respectively） （all P〈0.05）; In the Apelin-13 treatment group, their mRNA expression levels （0.663±0.085, 0.802±0.079, 0.752±0.097 and 0.509±0.119, respectively） were higher than in the diabetic model group, but lower than in the control group （all P〈0.05）. Liver G-6-P and PEPCK mRNA levels in the diabetic model group （1.727±0.05 and 1.309±0.130） were higher than in the control group （1.002±0.005 and 0.993±0.010） （both P〈0.05）, but lower than in the Apelin-13 treatment group （2.586±0.208 and 1.842±0.234） （both P〈0.05）. Skeletal muscle PPAR-α mRNA levels in the diabetic model group （0.477±0.118） and the Apelin-13 treatment group （0.566±0.0780） were lower than in the control group （0.993±0.013） （both P〈0.05）, but showed no significant difference between the two experimental groups （P〉0.05）.ConclusionsApelin-13 increases the expression of the PPAR, ACSL1, and CPT1 genes in the liver and, to a certain extent, improves fatty acid oxidation metabolism in the liver in type 2 diabetic rats.It also increases the expression of the G-6-P and PEPCK genes, promotes gluconeogenesis in the liver, and may be related to the development of type 2 diabetes.In skeletal muscle, Apelin-13 increases GLUT4 gene expression, moderately improves skeletal muscle metabolism and may play a role in the regulation of oxidative stress.