Polysaccharides from Lanzhou Lily Attenuate Nonalcoholic Fatty Liver Disease Modifying the Gut Microbiota and Metabolite Profile

Nonalcoholic fatty liver disease (NAFLD) is closely related to gut microbiota due to the hepatic portal system, and utilizing natural polysaccharides as prebiotics has become a prospective strategy for treating NAFLD. However, the therapeutic effects and potential molecular mechanisms of Lanzhou Lily polysaccharides (LLP) on NAFLD remains unclear. Therefore, the alleviating effects of LLP on NAFLD induced by high-fat diet (HFD) were investigated. LLP treatment greatly ameliorated NAFLD by significantly reducing lipid accumulation and the levels of liver function markers in HFD-induced NAFLD mice, as evidenced by decreased serum levels of TG, TC, HDL-C and LDL-C. Furthermore, LLP administration reduced hepatic steatosis, as shown by H&E and Oil red O staining. LLP also inhibited the TNF-α and IL-1β expression, thereby reducing levels of hepatic proinflammatory cytokines. Furthermore, LLP restored gut microbiota dysbiosis (up-regulated Bacteroidota, Proteobacteria, Alistipes and Lachnospiraceae abundances, down-regulated Firmicutes, Verrucomicrobiota, Desulfobacterota and Turicibacter abundances), and regulated microbial metabolic pathways such as primary bile acid biosynthesis and amino acid metabolism. In addition, the resultes of Spearman's correlation analysis found that some key metabolites in these metabolic pathways were associated with intestinal microorganisms such as Desulfobacterota, Prevotellaceae-UCG-001, Colidextribacter and Alistipes. Therefore, our study suggests that LLP may has potential applications in the treatment of NAFLD by regulating gut microbiota and its metabolite profile.