低氧运动改善肥胖大鼠胰岛素抵抗中Caveolin的变化

Hypoxic Exercise Improves Caveolin in Obese Rats with Insulin Resistance

目的:观察低氧运动对大鼠骨骼肌胰岛素抵抗(insulin resistance,IR)的影响,并探究小窝蛋白(Caveolin)在该过程中的作用。方法:5周龄雄性SD大鼠46只,随机分为对照组和高脂组,进行8周高脂膳食喂养,通过测定胰岛素敏感性以及葡萄糖耐量试验,判断建模是否成功;建模成功大鼠随机分为常氧安静组(NC)、常氧运动组(NE)、低氧安静组(HC)和低氧运动组(HE),进行4周低氧运动干预。测定各组大鼠胰岛素敏感性,免疫荧光观察GLUT4在大鼠比目鱼肌细胞内的分布,Western blot测定比目鱼肌GLUT4、Caveolin-1、Caveolin-3的蛋白含量。结果:1)大鼠在8周高脂膳食后出现IR;2)4周低氧运动使得大鼠体重明显下降,且胰岛素敏感性明显升高,糖耐量受损程度减轻;3)低氧运动诱导GLUT4在比目鱼肌细胞膜上的分布明显增加,且GLUT4的蛋白表达增多;4)与NC组相比,HE组Caveolin-3的蛋白含量显著升高。结论:低氧运动能有效改善肥胖诱导的IR,同时可促进GLUT4的生成及其在骨骼肌细胞内分布,Caveolin-3含量在此过程中出现升高。

Objective： This study aimed at observing the influence of hypoxia and exercise on insulin resistance（IR） in rats＇ skeletal muscle,and exploring the role of Caveolins in this process. Methods： Forty-six five-weekold male SD rats were randomly divided into control group and high-fat-fed group for 8-week high fat diet. The fasting blood glucose,fasting insulin levels and glucose tolerance test were used to determine whether the model was successful. IR rats were divided into four groups： NC（control）,NE（exercise only）,HC（hypoxia only）,HE（hypoxia ＋ exercise）. NE and HE groups finished 4 weeks exercise. The insulin sensitivity of each group was measured,and the distribution of GLUT4 in soleus cells of rats was observed by immunofluorescence. The protein expressions of GLUT4,Caveolin-1 and Caveolin-3 in the soleus muscle were determined by Western Blot. Results： 1） After 8-week high-fat diet,the rats developed into insulin resistance. 2） After 4 weeks hypoxic exercise,the body weight of rats decreased significantly,and insulin sensitivity increased significantly,and impaired glucose tolerance was reduced. 3） Hypoxia exercise induced the distribution of GLUT4 on soleus cell membrane and the expression of GLUT4 protein increased. 4） Compared with group NC,the protein content of Caveolin-3 in HE group increased significantly. Conclusions： Hypoxia exercise can effectively improve the insulin resistance induced by obesity,and can promote the formation of GLUT4 and its distribution in skeletal muscle cells; the content of Caveolin-3 increases in this process.