AIM To evaluate the effects of phosphatase and tension homologue deleted on chromosome ten(PTEN) gene on collagen metabolism in hepatic fibrosis and the underlying mechanisms.METHODS rat primary hepatic stellate cells(HSCs) and human LX-2 cells were transfected with adenovirus containing c DNA constructs encoding wild-type PTEN(Ad-PTEN), PTEN mutant G129 E gene(Ad-G129E), and r NA interference constructs targeting the PTEN sequence PTEN short hairpin r NA to up-regulate and downregulate the expression of PTEN. HSCs were assayed using fluorescent microscopy, real-time polymerase chain reaction, and western blotting. Moreover, a CCl_4-induced rat hepatic fibrosis model was established to investigate the in vivo effects. Hematoxylin and eosin, and Masson’s trichrome were used to assess the histological changes. The expression of collagen Ⅰ and Ⅲ was assessed using immunohistochemistry and western blot analysis.RESULTS Elevated expression of PTEN gene reduced serum levels of alanine transaminase and aspartate transaminase, decreased collagen deposition in the liver, and reduced hepatocyte necrosis. In contrast, knockdown of PTEN expression had an opposite effect, such as increased collagen deposition in the liver, and was molecularly characterized by the increased expression of matrix metalloproteinase(MMP)-13(P < 0.01) and MMP-2(P < 0.01), as well as decreased expression of the tissue inhibitor of metalloproteinase(TIMP)-1(P < 0.01) and TIMP-2(P < 0.01).CONCLUSION These data indicated that gene therapy using recombinant adenovirus encoding PTEN might be a novel way of treating hepatic fibrosis. AIM To evaluate the effects of phosphatase and tension homolog deleted on chromosome ten (PTEN) gene on collagen metabolism in hepatic fibrosis and the underlying mechanisms. METHODS rat primary hepatic stellate cells (HSCs) and human LX-2 cells were transfected with adenovirus containing c DNA constructs encoding wild-type PTEN (PTEN), PTEN mutant G129 E gene (Ad-G129E), and r NA interference constructs targeting the PTEN sequence PTEN short hairpin r NA to up-regulate and downregulate the expression of PTEN. HSCs were assayed using fluorescent microscopy, real-time polymerase chain reaction, and western blotting. Moreover, a CCl_4-induced rat hepatic fibrosis model was established to investigate the in vivo effects. Hematoxylin and eosin, and Masson’s trichrome were used to assess the histological changes . The expression of collagen Ⅰ and Ⅲ was assessed using immunohistochemistry and western blot analysis. RESULTS Elevated expression of PTEN gene reduced serum levels of alanine tr In contrast, knockdown of PTEN expression had an opposite effect, such as increased collagen deposition in the liver, and was molecularly characterized by the increased expression of matrix metalloproteinase ( MMP-13 (P <0.01) and MMP-2 (P <0.01), as well as decreased expression of the tissue inhibitor of metalloproteinase (TIMP) -1 (P <0.01) and TIMP- 2 (P <0.01). CONCLUSION These data indicated that gene therapy using recombinant adenovirus encoding PTEN might be a novel way of treating hepatic fibrosis.