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目的:通过研究8周有氧运动对高脂饮食诱导胰岛素抵抗C57BL/6小鼠肝脏m TOR复合物1/2(m TOR Complex 1/2)以及胰岛素信号相关蛋白的影响,分析有氧运动/高脂饮食与m TORC1/C2和胰岛素信号通路蛋白磷酸化活性之间的关系,为全面理解有氧运动改善高脂饮食诱导机体胰岛素抵抗的机制提供理论依据。方法:选取50只4周龄、雄性C57BL/6小鼠随机分为正常饮食组(C组,n=10)和高脂饮食组(H组,n=40)。高脂饮食组小鼠饲以高脂饮食6周以建立胰岛素抵抗模型,6周后通过口服葡萄糖耐量实验(Oral Glucose Tolerance Test,OGTT)鉴定胰岛素抵抗成模小鼠。随后将胰岛素抵抗小鼠再次随机分为安静组(H组,n=10)和运动组(HE组,n=15),此两组小鼠继续饲以高脂饮食,同时对HE组施以8周、强度为75%VO2max的有氧跑台运动干预。实验结束后,采用OGTT检测小鼠葡萄糖耐量,ELISA法测定空腹血清胰岛素水平,Western Blot检测肝脏Akt/m TOR信号通路相关蛋白磷酸化水平,并通过免疫共沉淀方法检测小鼠肝脏Raptor-m TOR及Rictor-m TOR结合水平。结果:与C组相比,H组小鼠体重、血清胰岛素水平均显著升高,口服葡萄糖耐量下降,肝脏胰岛素信号通路相关蛋白p Akt S473、p Akt T308、p IRS1S307、p AMPKαT172磷酸化水平下降,p S6K1T389磷酸化水平升高。免疫共沉淀检测发现Raptor-m TOR结合水平上升,Rictor-m TOR结合水平下降,即m TORC1蛋白表达水平升高,m TORC2蛋白表达水平减低;与H组相比,HE组小鼠体重、血清胰岛素水平均显著降低,口服葡萄糖耐量增高,肝脏胰岛素信号通路相关蛋白p AktS473、p AktT308、p IRS1S307、p AMPKαT172磷酸化水平有所提高,p S6K1T389磷酸化水平降低。Raptor-m TOR结合减少,Rictor-m TOR结合增多,即m TORC1蛋白表达水平降低,m TORC2蛋白表达水平增高。结论:8周有氧运动可改善高脂饮食诱导小鼠胰岛素敏感性,其机制可能与有氧运动激活小鼠肝脏Akt/m TORC2信号通路、抑制Akt/m TORC1信号通路,增强小鼠肝细胞胰岛素信号敏感性、改善胰岛素抵抗有关。
OBJECTIVE: To study the effect of 8-week aerobic exercise on m TOR Complex 1/2 and insulin-related protein in the liver of insulin resistance C57BL / 6 mice induced by high fat diet, and to analyze the effects of aerobic exercise / The relationship between high-fat diet and phosphorylation of mTORC1 / C2 and insulin signaling pathway provides a theoretical basis for a comprehensive understanding of the mechanism of aerobic exercise to improve the body’s insulin resistance induced by high-fat diet. Methods: Fifty four-week-old male C57BL / 6 mice were randomly divided into normal diet group (C group, n = 10) and high fat diet group (H group, n = 40). The mice in the high-fat diet group were fed with a high-fat diet for 6 weeks to establish an insulin resistance model. Six weeks later, insulin resistance-model mice were identified by oral Oral Glucose Tolerance Test (OGTT). Then, insulin resistant mice were randomly divided into quiet group (H group, n = 10) and exercise group (HE group, n = 15). The two groups of mice were fed with high fat diet, 8 weeks, intensity of 75% VO2max aerobic treadmill exercise intervention. After the experiment, the glucose tolerance of mice was measured by OGTT, the fasting serum insulin was measured by ELISA, the phosphorylation of Akt / m TOR signaling pathway was detected by Western Blot and the liver Raptor-m TOR was detected by co-immunoprecipitation And Rictor-m TOR binding levels. Results: Compared with group C, the body weight and serum insulin level of H group were significantly increased, the oral glucose tolerance decreased, and the phosphorylation of hepatic insulin signaling pathway related proteins p Akt S473, p Akt T308, p IRS1 S307 and p AMPKαT172 decreased , p S6K1T389 phosphorylation level increased. The results of co-immunoprecipitation showed that the binding of Raptor-m TOR increased and the binding of Rictor-m TOR decreased, that is, the expression of mTORC1 protein increased and the expression of mTORC2 protein decreased. Compared with H group, the body weight, Insulin levels were significantly lower oral glucose tolerance, liver insulin signal pathway related proteins p AktS473, p AktT308, p IRS1S307, p AMPKαT172 phosphorylation levels increased, p S6K1T389 phosphorylation decreased. Raptor-m TOR binding decreased, Rictor-m TOR binding increased, m TORC1 protein expression decreased, m TORC2 protein expression increased. CONCLUSION: Aerobic exercise at 8 weeks improves the insulin sensitivity in mice induced by high-fat diet. The mechanism may be related to the activation of Akt / m TORC2 signaling pathway, the Akt / m TORC1 signaling pathway, and the enhancement of mouse hepatocytes Insulin signal sensitivity, improve insulin resistance.