Jian-Gan-Xiao-Zhi Decoction Alleviates Inflammatory Response in Nonalcoholic Fatty Liver Disease Model Rats through Modulating Gut Microbiota

BACKGROUND: Jian-Gan-Xiao-Zhi decoction (JGXZ), composed of Salvia miltiorrhiza Bunge, Panax notoginseng, Curcuma zedoaria, and other 9 types of herbs, has demonstrated beneficial effects on nonalcoholic fatty liver disease (NAFLD). However, the mechanisms behind JGXZ's impact on NAFLD remain unknown. METHODS: In this study, a NAFLD rat model induced by a high-fat diet (HFD) received oral treatment of JGXZ (8 or 16 g crude herb/kg) for 12 weeks. The therapeutic effects of JGXZ on NAFLD model rats were investigated through blood lipid levels and pathological liver changes. 16S rRNA analysis was used to study the changes in gut microbiota after JGXZ treatment. The expressions of occludin and tight junction protein 1 (ZO-1) in the colon were investigated using immunostaining to study the effects of JGXZ on gut permeability. The anti-inflammatory effects of JGXZ were also studied through measuring the levels of IL-1β, IL-6, and TNF-α in the serum and liver. RESULTS: JGXZ treatment could decrease body weight and ameliorate dyslipidemia in NAFLD model rats. H&E and Oil Red O staining indicated that JGXZ reduced steatosis and infiltration of inflammatory cells in the liver. 16S rRNA analysis showed that JGXZ impacted the diversity of gut microbiota, decreasing the Firmicutes–to-Bacteroidetes ratio, and increasing the relative abundance of probiotics, such as Alloprevotella, Lactobacillus, and Turicibacter. Gut permeability evaluation found that the expressions of ZO-1 and occludin in the colon were increased after JGXZ treatment. Moreover, JGXZ treatment could decrease the levels of IL-1β, IL-6, and TNF-α in the serum and liver. CONCLUSIONS: Our study illustrated that JGXZ could ameliorate NAFLD through modulating gut microbiota, decreasing gut permeability, and alleviating inflammatory response.