Effects of a single local administration of cilostazol on neointimal formation in balloon-injured rat carotid artery

To elucidate if locally administered cilostazol, an inhibitor of cyclic AMP phosphodiesterase III, suppresses neointimal formation in balloon-injured carotid artery of the rat, 20 mg of cilostazol was topically applied using pluronic gel at the time of balloon injury. Rats were sacrificed 14 days after balloon injury to measure the extent of neointimal formation. Plasma and tissue concentrations of cilostazol were also measured at 1, 3, 7 and 14 days after topical application. The 5-bromo-2′-deoxyuridine (BrdU, a thymidine analogue) was given intraperitoneally to detect proliferation of smooth muscle cells in the injured media at 3 days after balloon injury. At 1 day after injury, plasma and tissue concentrations were 0.147±0.043 μg/ml and 1380 μg/g tissue. Although the plasma concentration of cilostazol was undetectable (