['Tadalafil can restore endothelial function and treat atherosclerosis. However, the effect of tadalafil on transplant arteriosclerosis remains unclear. In this study, we explore the effects of tadalafil on allograft vasculopathy.', 'Male Brow-Norway rats supplied aorta grafts for Male Lewis rats. All recipients were divided into 3 groups: saline as placebo (control) treated group, low dose tadalafil (0.5 mg/kg/day) treated group, and high dose tadalafil (1.0 mg/kg/day) treated group. Eight weeks after transplantation, the grafts were harvested at and analyzed by histological and Western blot analysis. An enzyme-linked immunosorbent assay (ELISA) was used for measure of plasma cyclic guanylate monophosphate (cGMP).', 'the treatment with tadalafil significantly alleviated the neointimal thickness of aortas compared with the control group (P<0.05). Tadalafil also remarkably enhanced the production of cGMP in plasma and expression of cGMP-dependent kinase I (PKG-I) and RhoA compared with control group (P<0.05).'] Does tadalafil attenuate graft arteriosclerosis of aortic transplant in a rat model?