ABSTRACT
BACKGROUND AND OBJECTIVES: Neointimal hyperplasia, which was caused by smooth muscle cell proliferation, was noted to occur after performing percutaneous coronary intervention. Phosphodiesterase type 5 (PDE5) inhibitor has been shown to inhibit smooth muscle cell proliferation. Udenafil is one of the PDE5 inhibitors, and it is also expected to inhibit smooth muscle cell proliferation and reduce neointimal hyperplasia. We investigated the effect of udenafil on the smooth muscle cell proliferation and neointimal hyperplasia that occurs after balloon injury in the carotid arteries of rats. MATERIALS AND METHODS: Smooth muscle cells were treated with 1 mM, 100 micrometer, 10 micrometer, 1 micrometer and 100 nM concentrations of udenafil. The viability of the smooth muscle cells was evaluated by MTT assay. The carotid arteries of rats were injured with a balloon catheter. Udenafil (100 micrometer, 10 micrometer and 1 micrometer) was applied on the carotid artery adventitia after balloon injury. At 21 days after treatment, the carotid arteries were harvested and stained with H & E. The neointima and media area were measured with a computerized image analysis program. RESULTS: In the in vitro experiment, treatment with 1 mM udenafil reduced smooth muscle cell viability by 68.8+/-4.42% compared to the control group. In the balloon injured rat carotid artery, treatment with 100 micrometer udenafil reduced the neointima area by 71.8% compared to the control group. CONCLUSION: Udenafil administration effectively inhibited smooth muscle cell proliferation and it reduced neointimal hyperplasia in the balloon-injured rat carotid artery.