Background Accumulative evidence showed that gut microbiota was important in regulating the development of nonalcoholic fatty liver disease (NAFLD). Hugan Qingzhi tablet (HQT), a lipid-lowering and anti-inflammatory medicinal formula, has been used to prevent and treat NAFLD. However, its mechanism of action is unknown. The aim of this study was to confirm whether HQT reversed the gut microbiota dysbiosis in NAFLD rats. Methods We established an NAFLD model of rats fed with a high-fat diet (HFD), which was given different interventions, and measured the level of liver biochemical indices and inflammatory factors. Liver tissues were stained with hematoxylin-eosin and oil red O. Changes in the gut microbiota composition were analyzed using 16S rRNA sequencing. Results The hepatic histology and biochemical data displayed that HQT exhibited protective effects on HFD-induced rats. Moreover, HQT also reduced the abundance of the Firmicutes/Bacteroidetes ratio in HFD-fed rats and modified the gut microbial species at the genus level, increasing the abundances of gut microbiota which were reported to have an effect on relieving NAFLD, such as Ruminococcaceae, Bacteroidales_S24-7_group, Bifidobacteria, Alistipes, and Anaeroplasma, and significantly inhibiting the relative abundance of Enterobacteriaceae, Streptococcus, Holdemanella, Allobaculum, and Blautia, which were reported to be potentially related to NAFLD. Spearman's correlation analysis found that [Ruminococcus]_gauvreauii_group, Lachnoclostridium, Blautia, Allobaculum, and Holdemanella exhibited significant (p < 0.001) positive correlations with triglyceride, cholesterol, low-density lipoprotein cholesterol, interleukin-6, interleukin-1β, tumor necrosis factor-α, and body weight and negative correlations with high-density lipoprotein cholesterol (p < 0.001). The norank_f__Bacteroidales_S24-7_group and Alistipes showed an opposite trend. Moreover, the HQT could promote flavonoid biosynthesis compared with the HFD group. Conclusion In summary, the HQT has potential applications in the prevention and treatment of NAFLD, which may be closely related to its modulatory effect on the gut microbiota.

No abstract

Background: Non-alcoholic fatty liver disease (NAFLD) is closely associated with metabolic disorders including hepatic lipid accumulation and inflammation. Alisol A 24-acetate, a triterpene from Alismatis rhizome, has multiple biologic activities such as hypolipidemic, anti-inflammatory and anti-diabetic. Thus we hypothesized that Alisol A 24 -acetate would have effect on NAFLD. The present study was conducted to investigate the therapeutic effects and potential mechanisms of Alisol A 24-acetate against hepatic steatosis in a free fatty acids (FFAs) induced NAFLD cell model. Methods: This study was divided into four groups including Control group, Model group (FFA group), Alisol A 24-acetate (FFA+A) group, Fenofibrate (FFA+F) group. Preventive role of Alisol A 24-acetate was evaluated using 10µM Alisol A 24-acetate plus 1 mM FFA (oleate:palmitate=2:1) incubated with HepG2 cells for 24 h, which was determined by Oil Red O Staining, Oil Red O based colorimetric assay and intracellular triglyceride (TG) content. Besides, the inflammatory cytokines tumor necrosis factor (TNF)- α, interleukin (IL)-6 levels as well as the protein and mRNA expressions that were involved in fatty acid synthesis and oxidation including Adiponectin, AMP-activated protein kinase (AMPK) α, peroxisome proliferator-activated receptor (PPAR) α, sterol regulatory element binding protein 1c (SREBP-1c), acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), carnitine palmitoyltransferase 1 (CPT1) and acyl coenzyme A oxidase 1 (ACOX1) were detected. Results: Alisol A 24-acetate significantly decreased the numbers of lipid droplets, Oil Red O lipid content, and intracellular TG content. Besides, inflammatory cytokines TNF-α, IL-6 levels were markedly inhibited by Alisol A 24-acetate. Furthermore, Alisol A 24-acetate effectively increased the protein and mRNA expressions of Adiponectin, the phosphorylation of AMPKα, CPT1 and ACOX1, whereas decreased SREBP-1c, the phosphorylation of ACC and FAS at both protein and mRNA levels. However, there was no significant effect on the protein and mRNA expressions of PPARα by Alisol A 24-acetate. Conclusions: These results demonstrated that Alisol A 24-acetate effectively ameliorated hepatic steatosis likely through Adiponectin, which activated AMPKα signaling pathways via down-regulating SREBP-1c, ACC, FAS and up-regulating CPT1 and ACOX1, and inhibited inflammation. Thereby, Alisol A 24-acetate could be a promising candidate for the treatment of NAFLD.