运动对胰岛素抵抗大鼠骨骼肌IRS-1与Tyr磷酸化及氧化应激的影响

目的研究运动对胰岛素抵抗大鼠骨骼肌IRS-1表达与酪氨酸磷酸化及MDA水平的影响,探讨运动改善骨骼肌胰岛素抵抗的机制。方法 22只SD雄性大鼠随机分为3组,空白对照组(CG)6只,胰岛素抵抗组(IRG)与胰岛素抵抗运动(EIRG)各8只,采用高脂膳食对IRG和EIRG大鼠诱导胰岛素抵抗模型。EIRG大鼠进行10周游泳训练,运动后测定各组大鼠骨骼肌IRS-1表达和其酪氨酸磷酸化水平及MDA含量。结果采用高脂膳食诱导胰岛素抵抗模型成功;运动干预后与CG比较I,RG大鼠骨骼肌IRS-1表达及其Tyr磷酸化水平显著降低(P<0.01),MDA含量与HOMA-IR显著升高(P<0.01);与IRG比较,EIRG大鼠骨骼肌IRS-1表达升高(P<0.05)I,RS-1Tyr磷酸化水平也显著增加(P<0.01);同时,胰岛素抵抗指数与MDA含量显著降低(P<0.05);MDA含量与IRS-1表达(r:-0.583;P:0.004)及其Tyr磷酸化水平(r:-0.634;P:0.002)均呈负相关。结论运动可提高胰岛素抵抗大鼠骨骼肌IRS-1蛋白表达,增加IRS-1 Tyr磷酸化水平,显著改善胰岛素抵抗;这可能主要与骨骼肌氧化应激降低诱导其IRS-1Tyr磷酸化水平增高有关。

The Effect of Exercise on Expression of Irs - 1, Tyr Phosphorylation and Oxidative Stress in Skeletal Muscle of Insulin Resistant Rats

Objective: Observant the effect of exercise on IRS-1expression,IRS-1Tyr phosphorylation and oxidative stress of insulin resistant rats’ skeletal muscle so that investigate the mechanism of exercise improve insulin resistance.Method: 22 SD rats were randomly divided into 3 groups: sedentary control group(CG,n=6),insulin resistance group(IRG,n=8) and insulin resistance plus exercise group(EIRG,n=8).The models of insulin resistance were induced by high fat feed,the EIRG rats were subjected to swimming for 10 weeks.Then IRS-1,IRS-1 Tyr phosphorylation and MDA of all rats’ skeletal muscle were assessed.Result: The IR model were induced,compared with CG,the expression of IRS-1 and the IRS-1 Tyr phosphorylation level were significantly decreased in IRG(P<0.01),the content of MDA and HOMA-IR were increased in IRG(P<0.01);Compared with IRG,the IRS-1 expression and IRS-1 Tyr phosphorylation level were significantly increased(P<0.05,P<0.01),MDA level and HOMA-IR were significantly reduced in EIRG(P<0.05);A negative correlation was found between MDA and the expression of IRS-1(r:-0.583,P:0.004),and between MDA and IRS-1Tyr phosphorylation(r:-0.634,P:0.002).Conclusion: Exercise can improve insulin resistance of rat through increases IRS-1 Tyr phosphorylation level duo to reduction of oxidative stress in skeletal muscle.