丝胶对2型糖尿病大鼠胰腺胰岛素PI3K-Akt信号通路的调节作用

目的探讨丝胶是否通过影响胰腺胰岛素PI3K-Akt信号通路发挥降血糖的作用。方法 36只雄性SD大鼠随机分为正常对照组、糖尿病模型组和丝胶治疗组,每组12只。采用高脂高糖饲料喂养联合链脲佐菌素(35mg/kg,2次,1次/d)连续腹腔注射法制作2型糖尿病大鼠模型,模型成功标准是空腹血糖≥11.1mmol/L。模型成功建立后,丝胶治疗组大鼠给予丝胶灌胃35d。采用ELISA法检测大鼠血清脂联素水平,Western blotting法和Real-time PCR法分别检测大鼠胰腺胰岛素受体(IR)、胰岛素受体底物-1(IRS-1)、磷脂酰肌醇-3-激酶(PI3K)和Akt蛋白和mRNA的表达情况。结果与糖尿病模型组比较,丝胶治疗组大鼠血清脂联素水平,胰腺IR、IRS-1、PI3K、Akt蛋白和mRNA的表达明显升高(P0.01,P0.05)。结论丝胶可通过上调糖尿病模型大鼠胰腺IR、IRS-1、PI3K和Akt的表达,改善糖尿病时胰腺胰岛素PI3K-Akt信号转导通路的异常,从而发挥降低血糖的作用。

Regulatory effects of sericin on pancreatic insulin PI3K/Akt signaling pathway in type 2 diabetic rats

Objective To investigate the effects of sericin on the blood glucose concentration by regulating pancreatic insulin P13K/Akt signaling pathway. Methods Thirty-six male SD rats were randomly divided into normal control group, diabetes mellitus model group and sericin treatment group, with 12 rats in each group. The type 2 diabetes mellitus rats model was induced by high calorie and high sugar diet plus intraperitoneal injection of streptozotocin (35mg/kg, 2 times, 1 time a day), and the standard for successfully establishing type 2 diabetes model was fasting blood glucose≥11.1mmol/L. The model rats were treated with sericin at the dose of 2.4g/kg/d for 35days by gastrogavage method. ELISA was used to detect the adiponectin level in serum, Western blotting and real time fluorescence quantitative PCR to detect the expression of insulin receptor (IR), insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3-kinase (PI3K) and protein kinase B (Akt/PKB) protein and mRNA in pancreatic tissues. Results Compared with model group, the serum adiponectin level, IR, IRS-1, PI3K and Akt/PKB protein and mRNA expression in pancreatic tissues of rats in sericin treatment group increased markedly (P＜0.01,P＜0.05). Conclusion Sericin can improve the abnormal changes of PI3K/Akt signaling pathway by up regulating IR, IRS-1, PI3K and Akt expression in pancreas of diabetes mellitus rats; Thereby, sericin play a role in lowering blood glucose.