Oxygen-derived free radicals as mediators of varicose vein wall damage

Varicose saphenous vein segments, segments of those veins with thrombophlebitis, and segments of normal veins obtained during operation on 23 patients were studied to define the pattern of pro-oxidative and antioxidative systems in these tissues. In segments of varicose veins (VV) the activity of superoxide dismutase (SOD) was significantly decreased as compared with normal veins: 7.8 +/- 2.9 vs 13.5 +/- 4.3 U/mg of protein (P < 0.05), but it was almost unchanged in the segments of VV with thrombophlebitis. The activity of glutathione reductase (GSH-R) in all studied segments was similar and amounted to about 12.0 IU. The content of free sulfhydryl (SH) groups, the concentration of ascorbic acid, and thiobarbituric acid-reactive substances (TBA-RS) in segments of VV were significantly decreased by 40%, 48%, and 47%, respectively (P < 0.05) as compared with segments of normal veins. The values of ascorbic acid and TBA-RS in the segments of VV with thrombophlebitis were increased by 13% and 16%, respectively, as compared with segments of normal veins. Decreased activities of SOD and reduced levels of free SH-groups and of ascorbic acid concentration in VV may indicate impaired antioxidant mechanisms in this tissue.