[Zuogui Jiangtang Qinggan Formula improves glucolipid metabolism in type 2 diabetes mellitus complicated with non-alcoholic fatty liver disease by regulating FoxO1/MTP/APOB signaling pathway]

This study aimed to investigate the effect and mechanism of Zuogui Jiangtang Qinggan Formula(ZGJTQG) on the glucolipid metabolism of type 2 diabetes mellitus(T2DM) complicated with non-alcoholic fatty liver disease(NAFLD). NAFLD was induced by a high-fat diet(HFD) in MKR mice(T2DM mice), and a model of T2DM combined with NAFLD was established. Forty mice were randomly divided into a model group, a metformin group(0.067 g·kg~(-1)), and high-and low-dose ZGJTQG groups(29.64 and 14.82 g·kg~(-1)), with 10 mice in each group. Ten FVB mice of the same age were assigned to the normal group. Serum and liver tissue specimens were collected from mice except for those in the normal and model groups after four weeks of drug administration by gavage, and fasting blood glucose(FBG) and fasting insulin(FINS) levels were measured. The levels of total cholesterol(TC), triglyceride(TG), and low-density lipoprotein(LDL) were detected by the single reagent GPO-PAP method. Very low-density lipoprotein(VLDL) was detected by enzyme-linked immunosorbent assay(ELISA). Alanine aminotransferase(ALT) and aspartate ami-notransferase(AST) were determined by the Reitman-Frankel assay. The pathological changes in the liver were observed by hematoxylin-eosin(HE) staining and oil red O staining. Real-time fluorescence-based quantitative polymerase chain reaction(real-time PCR) and Western blot were adopted to detect the mRNA and protein expression of forkhead transcription factor O1(FoxO1), microsomal triglyceride transfer protein(MTP), and apolipoprotein B(APOB) in the liver. The results showed that high-dose ZGJTQG could signi-ficantly reduce the FBG and FINS levels(P<0.05, P<0.01), improve glucose tolerance and insulin resistance(P<0.05, P<0.01), alleviate the liver damage caused by HFD which was reflected in improving liver steatosis, and reduce the serum levels of TC, TG, LDL, VLDL, ALT, and AST(P<0.05, P<0.01) in T2DM mice combined with NAFLD. The findings also revealed that the mRNA and protein expression of FoxO1, MTP, and APOB in the liver was significantly down-regulated after the intervention of high-dose ZGJTQG(P<0.05, P<0.01). The above study showed that ZGJTQG could effectively improve glucolipid metabolism in T2DM combined with NAFLD, and the mechanism was closely related to the regulation of the FoxO1/MTP/APOB signaling pathway.