耐力训练大鼠骨骼肌FAT/CD36表达及其与胰岛素敏感性的相关分析

Upregulated Expression of FAT/CD36 in Skeletal Muscle Induced by Endurance Training and Its Correlation with Insulin Sensitivity Index in Rats

目的:研究耐力训练对大鼠骨骼肌脂肪酸转位酶/CD36(FAT/CD36)表达的影响,并分析其与胰岛素敏感性指数(ISI)的相关关系。方法:将23只SD大鼠随机分成耐力训练组(T)(n=13)和安静对照组(C)(n=10)。T组大鼠每周进行6天、共7周的中等强度跑台耐力训练。7周后取肾周和睾丸周围脂肪组织称重,计算脂肪垫百分比;空腹取血测定总胆固醇(TC)、甘油三酯(TG)、非酯化脂肪酸(NEFA)、胰岛素(FINS)含量;取股直肌测定匀浆液FAT/CD36蛋白表达,并与ISI进行相关分析。结果:7周耐力训练后,T组大鼠体重和脂肪垫百分比均低于C组(P<0.01,P<0.01);T组大鼠血清TC、NEFA、FINS低于C组(P<0.01,P<0.05,P<0.05);T组大鼠股直肌匀浆液FAT/CD36蛋白含量、胰岛素敏感性指数(ISI)显著高于C组(P<0.01,P<0.05),且二者呈高度正相关(r=0.823,P<0.01)。结论:7周耐力训练可提高大鼠胰岛素敏感性,上调FAT/CD36的表达,以适应其介导的耐力训练脂肪分解代谢增强后骨骼肌脂肪酸转运的需求。

Objective To determine effect of endurance training on the expression of fatty acid translocase FAT/ CD36 in skeletal muscle of rats and the correlation between the expression and insulin sensitivity index（ISI）.Methods Male Sprague-Dawley rats were randomly assigned to two groupst：raining group（T,n=13）and control group（C,n=10）.Rats in group T were trained on treadmill six days a week for 7 weeks.Fat pads around testes and kidneys were weighted for calculating the percentage of fat pads vs body weight.Serum total cholesterol（TC）t,riglyceride（TG）,nonesterified fatty acids（NEFA）and fasting insulin（FINS）were measured.Western blot was used to detect FAT/ CD36 protein expression in quadriceps homogenate.The relation of FAT/CD36 expression to the ISI was analyzed.Results Markedly lower body weight,percentage of fat pads,TC,NEFA,and FINS were seen in group T after 7-week endurance training comparing to that in group C（P〈 0.01,P〈 0.01,P〈 0.01,P 〈0.05,and P 0.05r,espectively）.The FAT/CD36 protein expression and ISI were significantly higher in group T than in group C（P 〈0.01and P〈 0.05）.A significant correlation between FAT/CD36 and ISI were found in group T（r =0.823,P 〈0.01）,nut not in group C.Conclusion Seven-week endurance training improved insulin sensitivity and up-regulated the expression of FAT/CD36 for adapting the requirement of fatty acid transportation in skeletal muscle induced by enhanced lipid catabolism after endurance exercise.