Inhibitory effect of prostaglandin E₁ on intimal thickening following photochemically induced endothelial injury in the rat femoral artery

The inhibitory effect of prostaglandin E₁, which has an anti-platelet action and a vasodilating action via intracellular cyclic AMP elevation, was studied on intimal thickening in the rat femoral artery. A segment of the femoral artery was occluded by a platelet and fibrin-rich thrombus due to photochemical reaction between systemically administered Rose Bengal and transluminal green light which causes endothelial injury followed by platelet adhesion and aggregation at the site of photochemical reaction. Three weeks after endothelial injury, intimal thickening occurred at the irradiated site. Prostaglandin E₁ (0.3 μg/kg per min), administered as a continuous infusion 10 min before photochemical reaction significantly (P < 0.05) prolonged the time to occlusion of the femoral artery. In a separate experiment, prostaglandin E₁ (0.3 μg/kg per min) administered as a continuous infusion for 7 days just after endothelial injury significantly (P < 0.05) inhibited intimal thickening compared with a control group. In cultured rat-derived vascular smooth muscle cells, prostaglandin E₁ produced concentration-dependent inhibition of migration and proliferation, stimulated by platelet-derived growth factor. These results suggest that prostaglandin E₁ may be effective in preventing vascular restenosis after vascular surgery and angioplasty.