Tangganjian decoction ameliorates type 2 diabetes mellitus and nonalcoholic fatty liver disease in rats by activating the IRS/PI3K/AKT signaling pathway

Abstract Aim Previous clinical studies have demonstrated that tangganjian (TGJ), a modern Chinese prescribed medicine, has a clinical effect in the treatment of type 2 diabetes mellitus (T2DM) with nonalcoholic fatty liver disease (NAFLD). Our study aimed to investigate whether the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway is involved in this therapeutic effect. Materials and methods T2DM and NAFLD rat models were constructed and treated with three different concentrations of TGJ. Pioglitazone was used as a positive control, along with the model and normal groups. For analyses, blood and livers were collected. Levels of glucose and lipid metabolism indicators, including fasting insulin and total cholesterol, were determined. The expression levels of insulin receptor substrate (IRS), PI3K, and AKT were also determined by western blotting and immunohistochemistry. Liver tissues were stained with hematoxylin & eosin. Results In the high-dose TGJ-treated and positive groups, there was a significant increase in the HDL-C level and decreases in the levels of the fasting blood glucose, 2 h postprandial blood glucose, fasting insulin, triglyceride, total cholesterol, and low-density lipoprotein cholesterol, along with a significant increase in the expression of IRS, PI3K, and AKT in the liver. TGJ could also attenuate or counteract the effects of T2DM and NAFLD in the liver lobules. Conclusion A high concentration of TGJ can improve glucose and lipid metabolism by activating the IRS/PI3K/AKT signaling pathway.