Long-term diosbulbin B treatment induced liver fibrosis in mice

Airpotato yam is a traditional Chinese medicine used for treating thyroid disease and cancer in China. Diosbulbin B (DB) is reported to be the main hepatotoxic compound isolated from Airpotato yam. A variety of reports have shown the acute liver injury induced by DB in vivo. However, whether long-term administration of DB will cause liver fibrosis in mice is unknown. This study aims to investigate the liver fibrosis induced by long-term DB treatment in mice. C57BL/6 mice were orally given with DB (25, 50 mg/kg) for 1 or 2 month, respectively. Liver hydroxyproline content, hepatic collagen deposition and immune cells infiltration were increased in mice treated with DB (50 mg/kg) for 2 months. Serum amounts of hyaluronic acid and laminin were increased in mice treated with DB for 1 or 2 months. DB (50 mg/kg) induced hepatic stellate cells (HSCs) activation when mice were treated with DB for 2 months. Liver mRNA expression of Col1a1, Col1a2, Col3a1, fibronectin (Fn1), vimentin (Vim) and fibroblast-specific protein 1 (FSP1) were all increased in DB-treated mice. Hepatic protein expression of Vim, FSP1 and collagen 1 (COL1) were increased in DB-treated mice. Additionally, DB induced nuclear factor κB (NFκB) activation and increased the expression of pro-inflammatory molecules including tumor necrosis factor (TNF)-α, interleukin (IL)-6, intercellular cell adhesion molecule-1 (ICAM-1) and inducible nitric oxide synthase (iNOS) in mice. In conclusion, long-term administration of DB induced liver fibrosis in mice. HSCs activation, epithelial-mesenchymal transition (EMT) and liver inflammation contributed to DB-induced liver fibrosis in mice.