Yinzhihuang oral liquid protects against non-alcoholic steatohepatitis via modulation of the gut-liver axis in mice

Background: Yinzhihuang (YZH) oral liquid is a traditional Chinese medicine compound that has emerged as a promising therapeutic agent for non-alcoholic fatty liver disease (NAFLD). Here, we aimed to investigate the therapeutic effects of YZH on non-alcoholic steatohepatitis (NASH) and elucidate its underlying molecular mechanisms. Methods: Mice fed on a high-fat diet plus fructose/glucose drinking water (HFGD) were treated with YZH (30 mL/kg/d). The effects of YZH on mice with NASH were assessed through serological analysis and histological examination. Microbiota analysis based on 16S ribosomal ribonucleic acid (16S rRNA) and intestinal mucosal barrier function, serum inflammatory factors, hepatic macrophage infiltration, as well as hepatic toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), nuclear factor kappa B (NF Kappa B) pathway were carried out to explore the mechanism of YZH for treatment of NASH. Results: Results of the current study found that YZH effectively reduced body weight gain and adiposity and alleviated hepatocyte steatosis, hepatocyte ballooning, liver tissue lobular inflammation, as well as fibrosis. It also reduced the accumulation of triglycerides, cholesterol, and free fatty acids in the liver of the treated mice and normalized serum aspartate transaminase, alanine transaminase, and glucose levels as well as lipid metabolism. Meanwhile, YZH treatment significantly decreased the abundance of harmful bacteria, such as Mucispirillum, Helicobacter, and Desulfovibrionaceae. Mechanistically, the present study found that YZH upregulated the expression of tight junction proteins, decreased serum lipopolysaccharide, interleukin 6, and tumor necrosis factor alpha levels, and increased interleukin 10 levels in serum. In the liver, YZH alleviated macrophage infiltration, especially that of pro-inflammatory macrophages. Moreover, it was found that YZH inhibited the canonical TLR4, MyD88, NF Kappa B signaling pathway. Conclusions: In conclusion, YZH may be a new agent for the prevention of NASH. Further, YZH alleviates gut microbiota dysbiosis, restores the intestinal mucosal barrier, and inhibits the canonical TLR4, MyD88, NF Kappa B signaling pathway.