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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。
Objective To investigate the effect of exercise on IRS-1 expression, tyrosine phosphorylation and MDA level in skeletal muscle of rats with insulin resistance and to explore the mechanism of exercise on improving insulin resistance of skeletal muscle. Methods Twenty-two male Sprague-Dawley rats were randomly divided into three groups: control group (CG), insulin resistance group (IRG) and insulin resistance exercise (EIRG) of 8 rats. High fat diet was used to induce IRG and EIRG rats Insulin resistance model. EIRG rats were subjected to 10-week swimming training. The skeletal muscle IRS-1 expression, tyrosine phosphorylation level and MDA content were determined after exercise. Results The model of insulin resistance induced by high-fat diet was successful. Compared with CG, the IRS-1 expression and Tyr phosphorylation in skeletal muscle of I and RG groups were significantly decreased after exercise intervention (P <0.01), MDA content and HOMA-IR significantly increased (P <0.01). Compared with IRG group, IRS-1 expression in skeletal muscle of EIRG rats increased (P <0.05) and phosphorylation level of RS-1Tyr increased significantly (P <0.01). Meanwhile, insulin resistance index MDA content was significantly decreased (P <0.05); MDA content was negatively correlated with IRS-1 expression (r: -0.583; P: 0.004) and Tyr phosphorylation level (r: -0.634; P: 0.002) Conclusion Exercise can increase IRS-1 protein expression in skeletal muscle of IR rats and increase phosphorylation of IRS-1 Tyr, which can significantly improve insulin resistance. This may be mainly related to the increase of IRS-1 Tyr phosphorylation induced by decreased oxidative stress in skeletal muscle .