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目的探讨长期高蛋白饮食对营养性肥胖大鼠肝脏胰岛素受体底物2(IRS2)和葡萄糖转运子2(GLUT2)分子表达的影响。方法采用高脂高热量饲料喂养建立营养性肥胖Wistar大鼠模型(n=34)。随机分为高蛋白饲料组(HP组,n=12,蛋白热量占比36.7%)、高脂饲料组(HF组,n=11,脂肪热量占比38.3%)和普通饲料组(NC组,n=11),饲养24周。检测其空腹血糖(FBG)、空腹胰岛素(FINS)水平,计算胰岛素敏感指数(QUIC-KI);检测其肝脏IRS2、GLUT2的mRNA和蛋白表达。结果 HP组与NC组相比,胰岛素敏感指数(QUICKI)增高11.31%(P<0.05),IRS2 mRNA和蛋白含量分别提高16%(P<0.05)和24%(P<0.05);GLUT2分别提高24%(P<0.05)和25%(P<0.05);而HF组上述指标与NC组相比均有明显降低(P<0.05)。结论 长期等热量高蛋白饮食显著上调肝脏IRS2、GLUT2表达水平。可能是长期高蛋白饮食对营养性肥胖大鼠胰岛素敏感性改善的重要分子机制之一。
Objective To investigate the effects of long-term high-protein diet on the expression of hepatic insulin receptor substrate 2 (IRS2) and glucose transporter 2 (GLUT2) in rats with nutritional obesity. Methods Nutritional Wistar rats model was established by feeding high-fat and high-calorie diet (n = 34). They were randomly divided into high protein diet group (HP group, n = 12, protein heat accounted for 36.7%), high fat diet group (HF group, n = 11, fat calorie 38.3% n = 11) for 24 weeks. The fasting blood glucose (FBG) and fasting insulin (FINS) were measured and the insulin sensitivity index (QUIC-KI) was calculated. The mRNA and protein expression of IRS2 and GLUT2 in the liver were detected. Results Compared with NC group, the insulin sensitive index (QUICKI) increased by 11.31% (P <0.05) and the IRS2 mRNA and protein content increased by 16% (P <0.05) and 24% (P < 24% (P <0.05) and 25% (P <0.05) respectively. However, the above indexes in HF group were significantly lower than those in NC group (P <0.05). Conclusion Long-term isothermal high-protein diet significantly up-regulated the expression of IRS2 and GLUT2 in liver. It may be one of the important molecular mechanisms for the long-term high protein diet to improve insulin sensitivity in rats with nutritional obesity.