余甘子提取物对糖尿病大鼠肌肉和脂肪组织胰岛素信号通路的影响

Effects of Phyllanthus Emblica extracts on the insulin signal pathway in muscle and fat tissues of diabetic rats

背景:余甘子具有明显的降血糖作用,但其作用机制尚不清楚。目的:观察余甘子提取物对大鼠骨骼与脂肪组织中胰岛素信号通路相关蛋白的影响。方法:将30只SD大鼠随机等分为对照组、模型组和余甘子组,后2组以腹腔注射链脲佐菌素建立糖尿病大鼠模型。余甘子组用余甘子提取液灌胃6周,模型组和对照组灌胃同体积的蒸馏水。结果与结论:与对照组相比,糖尿病大鼠的体质量、空腹血糖、空腹胰岛素和胰岛素抵抗指数均显著升高(P<0.05),脂肪和肌肉组织磷脂酰肌醇-3-激酶、蛋白激酶BmRNA及葡萄糖转运蛋白4mRNA和蛋白水平显著下降(P<0.05,P<0.01),灌胃余甘子提取物6周后,余甘子组大鼠体质量、空腹血糖、空腹胰岛素和胰岛素抵抗指数均比模型组下降(P<0.05),脂肪和肌肉组织磷脂酰肌醇-3-激酶、蛋白激酶B和葡萄糖转运蛋白4mRNA水平明显增加(P<0.01,P<0.05),且脂肪组织葡萄糖转运蛋白4蛋白表达增加(P<0.01),但肌肉组织葡萄糖转运蛋白4蛋白差异没有显著性意义。提示余甘子提取物可调控胰岛素介导的磷脂酰肌醇-3-激酶/蛋白激酶B/葡萄糖转运蛋白4信号转导通路,发挥降血糖作用。

BACKGROUND： Phyllanthus Emblica has a significant hypoglycemic effect. However, its mechanism is not clear. OBJECTIVE： To explore the effects of Phyllanthus Emblica extracts on the proteins related to the insulin signal pathway in rat bone and fat tissues. METHODS： A total of 30 SD rats were randomly divided into control group, model group and Phyllanthus Emblica group. Rats in the latter two groups were intraperitoneally injected with streptozotocin to construct diabetic model. Rats in the Phyllanthus Emblica group were administrated with Phyllanthus Emblica extracts by gavage for 6 weeks; rats in the model group and the control group were administrated with distilled water of the same volume by gavage. RESULTS AND CONCLUSION： Compared with the control group, the body mass, fasting blood glucose, fasting insulin and insulin resistance index in diabetic rats increased significantly （P 0.05）; while the mRNA and protein levels of phosphatidylinositol-3-kinase, protein kinase B and glucose transporter 4 in the fat and muscle tissues decreased significantly （P 0.05, P 0.01）. The body mass, fasting blood glucose, fasting insulin and insulin resistance index in the Phyllanthus Emblica rats at 6 weeks after the gavage of Phyllanthus Emblica extracts was lower than those of the model rats; while the mRNA levels of phosphatidylinositol-3-kinase, protein kinase B and glucose transporter 4 in fat and muscle tissues increased significantly （P 0.01, P 0.05）. The protein expression of glucose transporter 4 in the fat tissues increased （P 0.01）. However, there was no significant difference between the protein expressions of glucose transporter 4 in the muscles. These findings indicate that Phyllanthus Emblica extracts can achieve hypoglycemic effects by regulating insulin-mediated phosphatidylinositol-3- kinase/protein kinase B/glucose transporter protein 4 signal transduction pathway.