Wulingsan alleviates metabolic dysfunction-associated steatotic liver disease through regulating gut microbiota-bile acid axis.

Abstract

BACKGROUND: Metabolic dysfunction-associated Steatotic Liver Disease (MASLD) is closely linked to gut microbiota disorders and bile acid imbalance. Wulingsan (WLS) have shown promise in regulating these pathways, but its mechanism of action unclear. This study aimed to evaluate the therapeutic effect of WLS on the rat MASLD model from the perspectives of intestinal microbiota composition and bile acid homeostasis. METHODS: The MASLD model was induced by a high-fat diet (HFD) and treated with different doses of WLS. Body weight and serum lipid profiles were monitored, inflammation were assessed to ELISA and RT-qPCR. H&E staining to evaluate histopathological changes. The 16S rRNA sequencing and LC-MS/MS analysis of gut microbiota composition and bile acid profiles. The fecal microbiota transplantation (FMT) experiment verified the effect of WLS on the gut microbiota. RESULTS: WLS treatment reduces the body weight of MASLD rats, improves lipid indicators, and inhibits inflammation and liver damage. The results of the FMT experiment indicated that transplantation of fecal microbiota from WLS-treated donors regulated the gut microbial composition and restored bile acid metabolic homeostasis in recipient rats. DISCUSSION: This study demonstrates that WLS treats MASLD by modulating multiple pathological pathways. Its effects in improving lipid metabolism and reducing hepatic inflammation align with the pathophysiological mechanisms of MASLD, indicating direct hepatoprotective actions. WLS intervention significantly restored gut microbiota diversity, increased the proportion of beneficial bacteria, suppressed potentially harmful bacterial genera, and corrected dysbiosis. FMT experiments further confirmed that gut microbes play a crucial role in mediating the therapeutic benefits of WLS. When microbiota from WLS-treated donors were transplanted into recipient rats, significant improvements were observed in metabolic markers, hepatic histopathology, and bile acid homeostasis. Collectively, the data support that WLS improves MASLD through a multi-targeted strategy centered on the gut-liver axis. CONCLUSION: WLS has an effective therapeutic effect on MASLD by improving lipid metabolism, reducing liver inflammation, reshaping the intestinal microbiota and normalizing bile acid homeostasis.