五味子酮通过调节AKT/GSK3信号通路改善2型糖尿病大鼠血糖的研究

Schisandrone improves the blood glucose in rats with type 2 diabetes mellitus by regulating the AKT/GSK3 signal pathway

目的探讨五味子酮的降血糖作用及其可能的作用机制。方法构建2型糖尿病(T2DM)大鼠模型,给予低、中、高剂量五味子酮灌胃处理后,评估其空腹血糖、K值与肝脏指数,并采用PAS染色检测肝组织的糖原含量。建立高糖(55 mmol·L^(-1))诱导的HepG2细胞模型,给予五味子酮或AKT抑制剂MK-2206干预后,分别采用NBDG法和比色法检测细胞的糖摄取和糖生成能力。采用Real-time PCR和Western blot法进一步检测T2DM大鼠肝组织和高糖诱导HepG2细胞中磷酸化AKT(p-AKT)和糖原合成酶(GSK3)的表达。结果与正常组相比,T2DM大鼠的空腹血糖和肝脏指数显著升高,胰岛素敏感性、糖原合成能力显著降低,高糖(55 mmol·L^(-1))诱导的HepG2细胞葡萄糖摄取显著减少、而生成显著增多。分子生物学实验结果显示,T2DM大鼠和高糖(55 mmol·L^(-1))诱导的HepG2细胞AKT的磷酸化水平显著下调,而GSK3的表达水平显著上调,给予五味子酮干预能够有效逆转上述改变,且该逆转作用可被AKT抑制剂MK-2206终止。结论五味子酮是一种潜在的降血糖药物,其降糖作用机制可能与调节AKT/GSK3信号通路有关。

Objective To determine the hypoglycemic effect of schisandrone and its possible action mechanism.Methods Type 2 diabetes mellitus(T2DM)rat model was established to assess its fasting glucose,K value and liver index after the gavage intervention with low,medium and high doses of schisandrone.The glycogen content of the liver tissue was detected by PAS staining.A high glucose(55 mmol·L^(-1))induced HepG2 cell model was established,and the glucose uptake and production capacity of the cells were detected by NBDG method and colorimetric method under the intervention of schisandrone or AKT inhibitor MK-2206,respectively.AKT phosphorylation and the glycogen synthase kinase-3(GSK3)expression in the liver tissues of T2DM rats and high glucoseinduced HepG2 cells were further detected by real-time PCR and Western blot.Results Compared with rats in the normal group,T2DM rats showed significantly higher fasting glucose lever and liver index,lower insulin sensitivity and glycogen synthesis,and the glucose uptake of HepG2 cells induced by high glucose(55 mmol·L^(-1))were decreased,while the production was much increased.Molecular biology experiments showed that the phosphorylation of AKT(p-AKT)level in T2DM rats and HepG2 cells was significantly down-regulated,but the expression level of GSK3 was significantly up-regulated.The above changes were all obviously reversed by schisandrone,but the effect of schisandrone on HepG2 cells was terminated by the AKT inhibitor MK-2206.Conclusion Schisandrone is a potential hypoglycemic drug,whose hypoglycemic mechanism may be related to the regulation of AKT/GSK3 signal pathway.