Effects of Apelin-13 on expression levels of glucose and lipid metabolism-related genes in the liver and skeletal muscle of diabetic rats / 中华老年医学杂志

ABSTRACT

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.Methods Forty 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 proliferatoractivated 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).Results Levels 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 Apelin13 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).Conclusions Apelin-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.