摘要
目的:探讨离心运动对2型糖尿病大鼠糖代谢和肌纤维类型的影响。方法:采用9周高脂饲养联合STZ注射构建2型糖尿病大鼠模型。将普通饲料组大鼠随机分为普通对照组(n=6)和普通运动组(n=9);将2型糖尿病模型大鼠随机分为糖尿病对照组(n=8)和糖尿病运动组(n=12)。运动组大鼠运动方案:坡度-5°,跑速16 m/min,每天训练60 min,每周训练5天,共4周。分别于运动前、后禁食12小时,取尾血测空腹血糖(FBG)和胰岛素(FINS),计算胰岛素抵抗指数(HOMA-IR)和胰岛素敏感指数(ISI)。运动后取比目鱼肌ATP-ase异染观察不同类型肌纤维构成情况,分析Ⅰ型肌纤维面积分数与ISI的相关性。结果:①与普通对照组相比,糖尿病对照组大鼠体重、FINS、ISI、Ⅰ型和Ⅱ型肌纤维平均横截面积、Ⅰ型肌纤维面积分数均显著降低(P<0.01),Ⅰ型和Ⅱ型肌纤维数量分数分别有降低和升高趋势(P=0.087),FBG、HOMA-IR和Ⅱ型肌纤维面积分数显著升高(P<0.01)。②4周离心运动后,与糖尿病对照组相比,糖尿病运动组大鼠HOMA-IR显著降低(P<0.01),Ⅰ型和Ⅱ型肌纤维平均横截面积显著增加(P<0.01,P=0.045),Ⅰ型和Ⅱ型肌纤维数量分数分别有降低和升高趋势(P=0.074),Ⅰ型和Ⅱ型肌纤维面积分数均无显著差异(P=0.654)。③Ⅰ型肌纤维面积分数与胰岛素敏感性指数呈中度正相关(r=0.485,P<0.01)。结论:骨骼肌容量的降低,尤其是Ⅰ型肌纤维的面积分数降低,是导致2型糖尿病代谢障碍的重要原因;4周离心运动在一定程度上恢复失衡的肌纤维构成,提高Ⅰ型肌纤维平均横截面积,从而降低2型糖尿病胰岛素抵抗,提高胰岛素敏感性。
Objective To explore the effect of the eccentric exercise on the glucose metabolism and muscle fiber type of type 2 diabetic rats.Methods Type 2 diabetics was induced in rats after 9-week high fat diet combined with streptozotocin(STZ)injection.The normal chow diet rats were randomly divided into a control group(C,n=6)and an exercise group(E,n=9),the type 2 diabetic rats were randomly divided into a diabetic control group(D,n=8)and a diabetic exercise group(DE,n=12).The exercise groups underwent 60-minute running at the slope of-5°,and the speed of 16 m/min,5 days a week for 4 weeks.The fasting blood glucose(FBG),fasting insulin(FINS),insulin resistance index(HOMA-IR)and insulin sensitivity index(ISI)were measured before and after the exercise.The soleus muscle of each group were stained using the ATP-ase to observe the composition of different types of muscle fibers,and to analyze the correlation between the area fraction of type I muscle fiber and ISI after the exercise.Results Compared with the control group,the average body weight,FINS,ISI,cross-sectional area of type I andⅡmuscle fibers and the area fraction of type I muscle fiber of the diabetic groups decreased significantly(P<0.01),the number fraction of type I andⅡmuscle fibers had a tendency to decrease and increase respectively(P=0.087),and the average FBG,HOMA-IR and the area fraction of type II muscle fiber increased significantly(P<0.01).After 4-week exercise,compared with the diabetic group,the average HOMA-IR of the diabetic exercise group decreased significantly(P<0.01),and the average cross-sectional area of type I and typeⅡmuscle fibers increased significantly(P<0.01,P=0.045),and the number fraction of type I and typeⅡmuscle fibers had a tendency to decrease and increase respectively(P=0.074).There were no significant differences in area fraction of type I and II muscle fibers between the diabetic and diabetic exercise groups(P=0.654).There was a moderately positive correlation between area fraction of type I muscle fibers and ISI(r=0.485,P<0.01).Conclusion The decrease of skeletal muscle capacity,especially that of the area fraction of type I muscle fibers,is an important cause of metabolic disturbance in rats with the type 2 diabetes.Four-week eccentric exercise can restore the unbalanced muscle fiber composition to some extent,and improve the average cross-sectional area of type I muscle fibers,thus reducing the insulin resistance and increasing the insulin sensitivity of rats with type 2 diabetes.
作者
王继
杨中亚
张龙
周越
Wang Ji;Yang Zhongya;Zhang Long;Zhou Yue(Physical Education School,Liupanshui Normal University,Liupamhui 553004,China;Sport Science School,Beijing Sport University,Beijing 100084,China)
出处
《中国运动医学杂志》
CAS
CSCD
北大核心
2020年第5期374-380,共7页
Chinese Journal of Sports Medicine
基金
贵州省教育厅青年科技人才成长项目(黔教合KY字[2018]368)
六盘水师范学院重点培育学科(LPSSYZDPYXK201710)
六盘水师范学院科技创新团队项目(LPSSYKJTD201502)。
关键词
离心运动
2型糖尿病
胰岛素抵抗
肌纤维类型
eccentric exercise
type 2 diabetes
insulin resistance
muscle fiber type
