ETHNOPHARMACOLOGICAL RELEVANCE: The coexistence of unhealthy diets and circadian rhythm disturbances contributes to the rising prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD), for which effective therapies are still lacking. Radix Bupleuri (BR) is a traditional Chinese medicine recognized for its hepatoprotective and lipid-modulating effects. However, the precise mechanisms by which it exerts therapeutic benefits in MASLD are not fully elucidated.
AIM OF THE STUDY: This study aimed to clarify the protective effects of BR alleviates MASLD in rats and to thoroughly explore its possible action pathways and molecular mechanisms.
MATERIALS AND METHODS: To establish MASLD models, rats underwent combined high-fat diet feeding and chronic circadian rhythm disruption (HFD-CRD) via a phase-delaying light-dark cycle (12 h light/12 h dark, with an 8 h delay in light onset every 48 h), followed by 6-week oral administration of BR fractions of varying polarities. Positive controls included Bicyclol and Melatonin. Physiological and biochemical assessments included body weight, liver and epididymal fat mass, locomotor activity, fasting blood glucose, oral glucose tolerance, serum lipid profile, and liver function markers. Hepatic steatosis was evaluated by H&E staining. Mechanistic insights were obtained via hepatic transcriptomics, untargeted metabolomics, targeted bile acid profiling, and qPCR validation.
RESULTS: BR treatment, particularly the high polarity fraction of BR (BH), significantly reduced body weight gain, hepatic steatosis, serum ALT and AST levels, and improved glucose tolerance, lipid metabolism, and locomotor activity. Metabolomics revealed BH-mediated normalization of 25 dysregulated liver metabolites, particularly bile acid derivatives. Transcriptomics demonstrated that BH reversed HFD-CRD-induced transcriptional alterations, primarily enriching in bile secretion and insulin signaling pathways. Integrated metabolomic-transcriptomic correlation analyses demonstrated that bile acid and glucolipid related genes were closely linked with metabolic phenotypes. Targeted bile acid quantification confirmed that BH comprehensively restored the dysregulated bile acid pool, with the DCA/HCA pair emerging as the most sensitive biomarker of metabolic remodeling. Functional validation further showed that BH reversed aberrant expression of bile acid secretion and glucose metabolism genes and activated hepatic and intestinal TGR5/GLP-1 signaling, thereby improving bile acid homeostasis, glucose metabolism, and gut barrier integrity.
CONCLUSIONS: BR ameliorates HFD-CRD-induced MASLD by restoring bile acid homeostasis, modulating glucolipid metabolism, and activating the TGR5/GLP-1 axis, expanding the pharmacological basis of BR for liver disorders and offering novel insights into multi-target MASLD therapeutics.
