Abstract: Objective To investigate the inhibitory effect of genistein on activation of hepatic stellate cells (HSCs) in vitro and the role of the autophagy pathway regulated by PPAR-γ in mediating this effect. Methods Cultured HSC-T6 cells were exposed to different concentrations of genistein for 48 h, and HSC activation was verified by detecting the expressions of α-SMA and α1(I) collagen; autophagy activation in the cells was determined by detecting the expressions of LC3-II and p62 using Western blotting. The autophagy inhibitor 3-MA was used to confirm the role of autophagy in genistein- induced inhibition of HSC activation. A PPAR-γ inhibitor was used to explore the role of PPAR-γ in activating autophagy in the HSCs. Results Genistein at concentrations of 5 and 50 μmol/L significantly inhibited the expressions of α-SMA and α1(I) collagen (P<0.05), markedly upregulated the expressions of PPAR-γ and the autophagy-related protein LC3-II (P<0.05) and significantly down-regulated the expression of the ubiqutin-binding protein p62 (P<0.05) in HSC-T6 cells. The cells pretreated with 3-MA prior to genistein treatment showed significantly increased protein expressions of α-SMA and α1(I) collagen compared with the cells treated with genistein only (P<0.05). Treatment with the PPAR-γ inhibitor obviously lowered the expression of LC3-II and enhanced the expression p62 in genistein-treated HSC-T6 cells, suggesting the activation of the autophagy pathway. Conclusion PPAR-γ- regulated autophagy plays an important role in mediating genistein-induced inhibition of HSC activation in vitro.