高脂饮食诱导肥胖模型大鼠骨骼肌组织蛋白酪氨酸磷酸酯酶1B和胰岛素受体底物2的表达

背景:外周组织的胰岛素抵抗是2型糖尿病的主要病因。目的:观察高脂饮食诱导的肥胖大鼠骨骼肌中蛋白酪氨酸磷酸酯酶1B和胰岛素受体底物2的表达。方法:将20只SD大鼠随机等分为对照组和高脂组,分别给予常规饲料和高脂饲料喂养12周。结果和结论:与对照组相比,高脂组大鼠胰岛素敏感指数显著降低(P<0.01),大鼠葡萄糖耐量受损,胰岛素释放试验提示葡萄糖刺激的胰岛素第一时相分泌受损,骨骼肌组织中蛋白酪氨酸磷酸酯酶1B蛋白表达水平明显增加(P<0.01),骨骼肌中胰岛素诱导的胰岛素受体底物2磷酸化程度降低(P<0.01)。提示高脂饮食诱导的肥胖大鼠骨骼肌中蛋白酪氨酸磷酸酯酶1B蛋白表达量升高,使胰岛素诱导的胰岛素受体底物2磷酸化程度降低,可能是肥胖导致胰岛素抵抗的机制之一。

Expression of protein-tyrosine phosphatase 1B and insulin receptor substrate 2 in the skeletal muscle of rats with insulin resistance induced by high-fat diet

BACKGROUND:Insulin resistance in the peripheral tissue is a major cause of type 2 diabetes mellitus.OBJECTIVE:To observe the expression of protein tyrosine phosphatase 1B (PTP-1B) and insulin receptor substrate 2 (IRS-2) in the skeletal muscle of rats with insulin resistance induced by high-fat diet.METHODS:Twenty SD rats were randomly divided into normal control group with 10 rats and high-fat diet group with 10 rats.Rats in the two groups were fed with normal diet and high-fat diet for 12 weeks,respectively.RESULTS AND CONCLUSION:The insulin sensitive index was significantly decreased in the high-fat diet rats compared with the normal rats (P < 0.01).In obese rats,glucose tolerance and the acute first-phase insulin secretory response to glucose were impaired.The protein level of PTP-1B in the skeletal muscle of obese rats was significantly increased compared with the control group (P < 0.01).Insulin-stimulated IRS-2 phosphorylation in the skeletal muscle was reduced in the obese rats (P < 0.01).These indicate that the increased PTP-1B level and the reduced insulin-stimulated IRS-2 phosphorylations in the skeletal muscle seem to play an important role in the insulin resistance induced by high-fat diet.