Inhibitory effect of photooxidation on intimal and medial thickening of saphenous vein

Background. The inhibitory effect of short-term photooxidation on medial and neointimal proliferation of human saphenous vein was investigated. Methods. Culture medium–filled surgically prepared saphenous vein segments were photooxidized in 0.01% methylene blue solution for 5 minutes. Photooxidized and nonphotooxidized saphenous veins were checked for viability of endothelial cells by culturing vein segments for 21 days followed by histologic and immunohistochemical studies. Results. Endothelial cells of saphenous vein segments remained unaffected after photooxidation. Both the intima and media of nonphotooxidized veins became highly cellular and thickened because of the proliferation and migration of smooth muscle cells. Like precultured fresh saphenous vein, intimal (0.031 ± 0.017 mm; p = 0.0067) and medial thicknesses (0.702 ± 0.123 mm; p < 0.0001) and proliferating cell nuclear antigen–positive cell count (14 ± 8/mm2; p = 0.0005) of cultured photooxidized veins were significantly less than those of cultured nonphotooxidized veins (intimal thickness, 0.059 ± 0.041 mm; medial thickness, 0.997 ± 0.228 mm; proliferating cell nuclear antigen positive cell count, 34 ± 16/mm2. Conclusions. Methylene blue–induced short-term photooxidation is effective in inhibition of intimal and medial thickening of saphenous vein.