Effect of salvianolic acid B on Smad3 expression in hepatic stellate cells

BACKGROUND: Salvianolic acid B (SA-B), one of water soluble compounds derived from Radix salviae miltiorrhizae, had good action against liver fibrosis of patients with chro- nic hepatitis. Hepatic stellate cells (HSCs) is the cellular re- source for liver fibrogenesis, while transforming growth factor-β1 (TGF-β1) is most potent fibrogenic factor. In this study we investigated the mechanism of SA-B action against liver fibrosis relating to the interference with TGF- β1 signaling at HSC. METHODS: Hepatic stellate cells (HSCs) were isolated, cultured, and incubated with SA-B. The TGF-β1 content in the supernatant of subcultured HSCs was assayed with ELISA. Type I collagen and Smad3 protein in TGF-β1-sti- mulated primarily cultured HSCs for 4 days were detected by Western blot. RESULTS: TGF-β1 secreted in activated HSCs was more than in primary HSCs, and SA-B significantly decreased TGF-β1 secretion in activated HSCs. TGF-β1 increased the expression of type I collagen and Smad3 protein in d4 pri- mary HSCs, while SA-B inhibited their expression. CONCLUSIONS: SA-B inhibits TGF-β1 secretion in activa- ted HSCs and counteracts the expression of TGF-β1 stimu- lated type I collagen and Smad3. These actions are associat- ed with the effect of SA-B on liver fibrosis.