Liver Lipidomics Analysis Revealed the Protective mechanism of Zuogui Jiangtang Qinggan Formula in type 2 diabetes mellitus with non-alcoholic fatty liver disease

ETHNOPHARMACOLOGICAL RELEVANCE

Hepatic steatosis, a hallmark of non-alcoholic fatty liver disease (NAFLD), represents a significant global health issue. Liver lipidomics has garnered increased focus recently, highlighting Traditional Chinese Medicine's (TCM) role in mitigating such conditions through lipid metabolism regulation. The Zuogui Jiangtang Qinggan Formula (ZGJTQGF), a longstanding TCM regimen for treating Type 2 Diabetes Mellitus (T2DM) with NAFLD, lacks a definitive mechanism for its lipid metabolism regulatory effects.

AIM OF THE STUDY

This research aims to elucidate ZGJTQGF's mechanism on lipid metabolism in T2DM with NAFLD.

MATERIALS AND METHODS

The study, utilized db/db mice to establish T2DM with NAFLD models. Evaluations included Hematoxylin-Eosin (HE) and Oil Red O stainedstaining of liver tissues, alongside biochemical lipid parameter analysis. Liver lipidomics and Western blotting further substantiated the findings, systematically uncovering the mechanism of action mechanism.

RESULTS

ZGJTQGF notably reduced body weight, and Fasting Blood Glucose (FBG), enhancing glucose tolerance in db/db mice. HE, and Oil Red O staining, complemented by biochemical and liver lipidomics analyses, confirmed ZGJTQGF's efficacy in ameliorating liver steatosis and lipid metabolism anomalies. Lipidomics identified 1571 significantly altered lipid species in the model group, primarily through the upregulation of triglycerides (TG) and diglycerides (DG), and the downregulation of phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Post-ZGJTQGF treatment, 496 lipid species were modulated, with increased PC and PE levels and decreased TG and DG, showcasing significant lipid metabolism improvement in T2DM with NAFLD. Moreover, ZGJTQGF's influence on lipid synthesis-related proteins was observed, underscoring its anti-steatotic impact through liver lipidomic alterations and offering novel insights into hepatic steatosis pathogenesis.

CONCLUSIONS

Liver lipidomics analysis combined with protein verification further demonstrated that ZGJTQGF could ameliorate the lipid disturbance of TG, DG, PC, PE in T2DM with NAFLD, as well as improve fatty acid and cholesterol synthesis and metabolism through De novo lipogenesis pathway.

[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.

[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.