[Effect of Zuogui Jiangtang Qinggan Formula on lipid metabolism in db/db mouse model of type 2 diabetes mellitus complicated with non-alcoholic fatty liver disease].

This study aims to explore the effect of Zuogui Jiangtang Qinggan Formula(ZGJTQGF) on the lipid metabolism in the db/db mouse model of type 2 diabetes mellitus(T2DM) complicated with non-alcoholic fatty liver disease(NAFLD) via the insulin receptor(INSR)/adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK)/sterol-regulatory element-binding protein 2(SREBP-2) signaling pathway. Twenty-four db/db mice were randomized into positive drug(metformin, 0.067 g·kg~(-1)) and low-(7.5 g·kg~(-1)) and high-dose(15 g·kg~(-1)) ZGJTQGF groups. Six C57 mice were used as the blank group and administrated with an equal volume of distilled water. The mice in other groups except the blank group were administrated with corresponding drugs by gavage for 6 consecutive weeks. At the end of drug administration, fasting blood glucose(FBG) and blood lipid levels were measured, and oral glucose tolerance test was performed. Compared with the blank group, the mice treated with ZGJTQGF showed decreased body mass and liver weight coefficient, lowered levels of FBG, total cholesterol(TC), triglyceride(TG), and low-density lipoprotein(LDL), and weakened liver function. The pathological changes and lipid accumulation in the liver tissue were examined. Western blot was employed to measure the protein levels of INSR, AMPK, p-AMPK, and SREBP-2. Compared with the blank group, the model group showed down-regulated protein levels of INSR and p-AMPK/AMPK and up-regulated protein level of SREBP-2. Compared with the model group, high-dose ZGJTQGF up-regulated the protein levels of INSR and p-AMPK/AMPK and down-regulated the protein level of SREBP-2. Low-dose ZGJTQGF slightly up-regulated the protein levels of INSR and p-AMPK/AMPK and down-regulated the protein level of SREBP-2, without significant differences. The results suggested that ZGJTQGF may alleviate insulin resistance and improve lipid metabolism in db/db mice by activating the INSR/AMPK/SREBP-2 signaling pathway.