8周游泳运动对高脂饮食诱导胰岛素抵抗大鼠骨骼肌细胞自噬的影响

Effect of 8-Week Swimming Exercise on Autophagy in Rats with Insulin Resistance Induced by High-Fat Diet

目的:探讨有氧运动对胰岛素抵抗大鼠骨骼肌细胞自噬及其相关蛋白表达水平的影响。方法:雄性SD大鼠随机分为3组:正常饮食组(ND)、高脂饮食组(HFD)和高脂饮食+运动组(HFD+EXE)。HFD和HFD+EXE组大鼠实验全程进行高脂饮食喂养,HFD+EXE组于高脂饮食喂养8周后施以游泳运动干预,60 min/天,6天/周,持续8周。透射电镜观察腓肠肌内自噬溶酶体的数量,Western blot检测骨骼肌自噬蛋白LC3-II、LC3-II/LC3-I和Beclin-1表达情况。结果:HFD组FBG、HOMA-IR较ND组明显升高;运动干预后,HFD+EXE组FBG和HOMA-IR均有下降趋势。超微结构方面,HFD组线粒体出现明显损伤,部分线粒体可见空泡变性,HFD+EXE组线粒体损伤有明显好转,但各组均未发现自噬小体。与ND组比较,HFD组LC3-II、Beclin1自噬蛋白和LC3-II/LC3-I显著降低;运动干预后LC3-II、LC3-II/LC3-I和Beclin1出现升高趋势。结论:有氧运动可明显增加高脂饮食诱导的胰岛素抵抗骨骼肌的细胞自噬水平,进而维持骨骼肌的正常功能。

Objective:To explore the effect of aerobic exercise on the changes of autophagy in skeletal muscle cells in rats with insulin resistance and the expression of autophagy-related protein.Methods:Thirty-six male SD rats were randomly divided into three groups:Normal Diet group(ND,n=12),High Fat Diet group(HFD,n=12)and High Fat Diet+Exercise intervention group(HFD+EXE,n=12).Rats of HFD and HFD+EXE group were fed high fat diet in the whole experiment.Swimming was used for aerobic exercise intervention,60 min per day,six days per week,and the intervention lasted 8 weeks.The autophagosome was observed by transmission electron microscope in gastrocnemius muscle,and the expression of LC3-I、LC3-II、LC3-II/LC3-I and Beclin-1 were tested by Western blot.Results:Compared with ND group,fasting blood glucose and HOMA-IR of HFD group increased significantly.After exercise intervention,both the FBG and HOMA-IR in HFD+EXE group had a downward trend.In the ultrastructure,the mitochondria of the HFD group showed obvious damage,and some mitochondria were vacuoles.Conclusion:Aerobic exercise can increase the autophagy level of skeletal muscle cells of insulin resistance rats induced by high-fat diet,and protect skeletal muscle cells.Mitochondrial injury in HFD+EXE group was significantly improved,but no autophagy was found in each group.Compared with ND group,LC3-II,Beclin1 and LC3-II/LC3-I in HFD group decreased significantly.The tendency of LC3-II,LC3-II/LC3-I and Beclin1 increased after exercise intervention.