Study on the hepatoprotective effects and mechanism of Alismatis Rhizoma extracts in bile duct ligation-induced liver fibrosis in mice

Liver fibrosis is a chronic liver injury caused by various pathogenic factors, leading to excessive accumulation of extracellular matrix such as collagen. It represents a common pathological hallmark during the progression of most chronic liver diseases. However, there is currently no universally recognized specific and effective drug for the clinical treatment of liver fibrosis. Therefore, this study investigates the effects of Alisma Rhizoma on bile duct ligation (BDL)-induced liver fibrosis and explores the potential pharmacological mechanisms. The animal experimental protocol was reviewed and approved by the Animal Welfare and Ethics Committee of Shanghai University of Traditional Chinese Medicine (registration No. PZSHUTCM2303280007), in compliance with relevant animal welfare and ethical standards. Mice were subjected to BDL to induce liver fibrosis. Mice were divided into five groups: sham operation group (Sham), model group (BDL), ethanol extract protection group (BDL+EE, 1.6 g·kg^-1), water extract protection group (BDL+WE, 4.0 g·kg^-1), obeticholic acid protection group (BDL+OCA, 10 mg·kg^-1). The results showed that both of EE and WE could attenuate BDL-induced liver fibrosis as evident by reduced serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT) activities, total bile acids (TBA) levels, and improved pathological conditions such as cholestasis, collagen deposition, inflammatory cell infiltration, and liver tissue necrosis. Notably, EE showed better efficacy than WE. Further studies showed that EE improved liver fibrosis dose dependently. EE treatment impaired the bile acids homeostasis in serum and liver, and recovered the hepatic mRNA expression of farnesoid X receptor (FXR) as well as the downstream genes including small heterodimer partner (SHP), cholesterol 7-alpha hydroxylase (CYP7A1) and bile salt export pump (BSEP). Further study also proved that the four major triterpenes in EE increased the transcriptional activities of FXR in vitro. This study provides a theoretical basis for the clinical application of Alisma Rhizoma in the prevention and treatment of liver fibrosis.