BACKGROUND: This study investigated the protective mechanism of Prostagladin E1 (PGE1) against intimal hyperplasia after vein interposition grafts in rabbits. It has been demonstrated that active oxygen species contribute to vascular smooth muscle cell growth via early cell cycle gene activation. We attempted to study whether PGE1 had an effect on the inhibition of the oxidative stress injury index (8-OHdG, MDA). METHODS: Forty-eight jugular vein grafts were inserted into the carotid arteries of male hyperlipidemic New Zealand white rabbits, which were divided into 2 groups (saline group and PGE1 group). Saline and Prostaglandin E1 (0.1 microgram/kg/min) were administered as a continuous infusion for 2 hours every day from just before graft interposition to harvest. The vein grafts were harvested at 6 hour, 1 day, 1 week, and 2 week after grafting and rapidly stored in liquid nitrogen ( 70oC). 8-OHdG was measured by using high performance liquid chromatography coupled with electrochemical detection (HPLC-EC), and malondialdehyde (MDA) was measured by using thiobarbituric acid (TBA) assay. PC 10 index and intimal thickness of the grafts were measured with a computer digitalized image analyzer. RESULTS: There was no difference in 8-OHdG levels between the saline and the PGE1 groups. PGE1 had more inhibitory effect on the MDA level as an oxidative stress injury index, but its action was restricted to 1 day. A morphometric analysis and an immunohistochemical study showed that the PGE1 group had more suppressive effects both in intimal thickeness and proliferating cell nuclear antigen (PCNA) expression than the saline group (p<0.05). CONCLUSION: These results suggest that PGE1 is effective in preventing intimal hyperplasia after vein interposition grafts in rabbits and may play a role in inhibiting oxidative stress injury.