Objective: To investigate the effect of adenoviral vector-mediated AT2R gene transfection on neointimal hyperplasia after rat carotid artery balloon injury. Methods :AT2R gene was transferred into rat carotid arteries by recombinant adenovirus pAd-AT2R after the establishment of rat carotid balloon injury restenosis model. The arteries were harvested on the 14th day after gene transfer. The efficiency of trans-gene delivery was measured by the expression of adenovirus-encoding green fluorescent protein (GFP) under fluorescent microscope. The expression of AT2R and PCNA (proliferating cell nuclear antigen) was e-valuated by RT-PCR, immunocytochemistry, immunofluorescence staining, confocal microscopy, respectively. The ratio of intimal to medial area (I/M) was quantified with images and determined by an image analysis system. Results: GFP-positive area in adventitia, media and the forming neointima was about 40%. Adenoviral delivery of rat AT2R gene up-regulated AT2R expression in balloon-injured rat carotid and reduced PCNA expression and I/M significantly in neointima(P<0. 01). Double immunofluorescence labeling of AT2R and PCNA also showed that AT2R gene transfer inhibited VSMCs proliferation in neointima. Conclusion: AT2R gene transfer may be a novel promising therapy to limit neointimal hyperplasia. Objective: To investigate the effect of adenoviral vector-mediated AT2R gene transfection on neointimal hyperplasia after rat carotid artery balloon injury. Methods: AT2R gene was transferred into rat carotid arteries by recombinant adenovirus pAd-AT2R after the establishment of rat carotid balloon injury restenosis model . The arteries were harvested on the 14th day after gene transfer. The efficiency of trans-gene delivery was measured by the expression of adenovirus-encoding green fluorescent protein (GFP) under fluorescent microscope. The expression of AT2R and PCNA (proliferating cell nuclear antigen ) was e -valuated by RT-PCR, immunocytochemistry, immunofluorescence staining, confocal microscopy, respectively. The ratio of intimal to medial area (I / M) was quantified with images and determined by an image analysis system. in adventitia, media and the forming neointima was about 40%. Adenoviral delivery of rat AT2R gene up-regulated AT2R expression in ballo on-injured rat carotid and reduced PCNA expression and I / M significantly in neointima (P <0.01). Double immunofluorescence labeling of AT2R and PCNA also showed that AT2R gene transfer inhibited VSMCs proliferation in neointima. Conclusion: AT2R gene transfer may be a novel promising therapy to limit neointimal hyperplasia.