AIM: To investigate the effects of adeno-associated virus (AAV) mediated expression of human interferon-γ for gene therapy in experimental hepatic fibrosisin vitro and in vivo.METHODS: We constructed the recombinant AAV encoding human INF-γ (rAAV- INF-γ) and took the primary rat hepatic stellate cells and carbon tetrachloride induced rats as the experimental hepatic fibrosis model in vitro and in vivo. Immunocytochemistry analysis was used to reveal the expression of α-SMA, the marker protein expressed in hepatic stellate cells. The mRNA expression of TGF-β, TIMP-L, and MMP-13 were analyzed by RT-PCR method. In vivo study, the hydroxyproline content in liver and serum AST, ALT were also detected.RESULTS: In vitro study, AAV vector could mediated efficient expression of human INF-γ,, which inhibit the activation of hepatic stellate cells, decrease the expression of α-SMA and mRNA of TIMP-1, TGF-β, with the MMP-13unchanged. In vivo study, the histological examination revealed that rAAV- INF-γ could inhibit the progression of the hepatic fibrosis. In the rAAV-INF-γ induced group,the hydroxyproline content and serum AST, ALT level were decreased to 177±28 μg/g wet liver, 668.5±140.0,458.4±123.5 U/L, compare with the fibrosis control group 236±31 μg/g wet liver, 1 019.1±276.3, 770.5±154.3 U/L,respectively (P＜0.01). mRNA expression of TIMP-1 in the rAAV-INF-γ induced rat liver was decreased while no significant change was observed in TGF-β and MMP-13.CONCLUSION: All these results indicated that rAAV-INF-γhas potential effects for gene therapy of hepatic fibrosis,which could inhibit the progression of hepatic fibrosis.