运动干预对高脂饮食大鼠脂类代谢异常和胰岛素敏感性的影响

Effects of exercise intervention on lipid metabolism abnormalities and insulin sensitivity in rats fed with high-fat diet

目的评估运动干预对高脂饮食大鼠脂类代谢异常和胰岛素敏感性的影响。方法30只雄性大鼠随机均分为三组。空白对照组(NC组)大鼠使用标准食物饲养;高脂饮食组(HF组)和运动干预组(SW组)行高脂饮食(由脂肪提供40%的热量)饲养。饲养16周后,SW组大鼠执行8周改进型Ploug游泳训练。采用高胰岛素-血糖钳夹实验测定大鼠即时血糖及基础胰岛素水平。定期测量大鼠体重并检测血清游离脂肪酸(FFA)和TG,记录肌肉TG沉积。实时定量PCR和Western blot分别检测大鼠后肢腓肠肌中肌肉素和葡萄糖转运体4(GLUT4)的mRNA和蛋白表达。结果运动干预前,与NC组比较,HF组和SW组大鼠体重增高(P<0.05)。运动干预后,SW组大鼠体重低于HF组(P<0.05)。HF组大鼠内脏脂肪、血清FFA和TG、内脏脂肪/体重比值高于NC组和SW组(P<0.05或P<0.01)。高胰岛素-血糖钳夹实验结果显示,HF组基础血清胰岛素水平高于NC组和SW组(P<0.05或P<0.01)。HF组大鼠肌肉TG沉积高于NC组和SW组(P<0.01),SW组大鼠肌肉TG沉积亦高于NC组(P<0.01)。HF组大鼠GLUT4mRNA和蛋白表达均低于NC组和SW组(P<0.01),而肌肉素mRNA和蛋白表达均高于NC组和SW组(P<0.01)。SW组大鼠肌肉素mRNA和蛋白表达亦高于NC组(P<0.01)。结论运动干预可以改善高脂饮食大鼠的脂类代谢异常和胰岛素敏感性,可能是通过增加GLUT4和减少肌肉素来促进脂类代谢、增强胰岛素敏感性。

Objective To evaluate the effects of exercise intervention on lipid metabolism abnormalities and insulin sensitivity in rats fed with high-fat diet. Methods Thirty male rats were randomly divided into three groups with 10 rats each. The rats in group NC were fed with standard food. The rats in groups of HF and SW were fed with high-fat diet（40% calories from fat）. The rats in group SW were given exercise intervention. After feeding for 16 weeks, the rats in group SW received modified Ploug swimming exercise for 8 weeks. The high insulin-blood glucose clamp test was used to determine the immediate blood glucose and basal insulin levels. The body weight, serum free fatty acid （FFA） and TG were measured periodically and the muscle TG deposition was recorded. Real-time quantitative PCR and Western blot were used to detect the mRNA and protein expressions of muselin and glucose transporter 4 （GLUT4） in the gastrocnemius muscle of hind legs. Results Before exercise intervention, the body weight of rats in groups of HF and SW was more than that of rats in group NC （P〈0. 05）. After exercise intervention,the body weight of rats in group SW was lower than that of rats in group HF（P〈0. 05）. The visceral fat, serum FFA and TG, visceral fat and body weight ratio in group HF were higher than those in groups of NC and SW（P〈0. 05 or P〈0. 01）. High insulin-blood glucose clamp test results showed that the basal serum insulin level in group HF was higher than that in groups of NC and SW（P〈0. 05 or P〈0. 01）. The muscle TG deposition in group HF was higher than that in groups of NC and SW（P〈0. 01）, which was higher in group SW than that in group NC （P〈0. 01）. The mRNA and protein expressions of GLUT4 were lower and muselin were higher in group HF than those in groups of NC and SW（P〈0. 01）. The mRNA and protein expressions of musclin in group SW were also higher than those in group NC （P~〈0. 01 ）. Conclusion Exercise intervention can improve lipid metabolism and insulin sensitivity in rats with high-fat diet by upregulating GLUT4 and downregulating musclin.