Water-soluble antioxidants inhibit macrophage recognition of oxidized erythrocytes

Effect of exogenously added water-soluble antioxidants on the mouse macroph age lectin-like receptor activity for oxidized erythrocytes was investigate d. A monolayer of thioglycollate-induced mouse peritoneal macrophages was p reincubated with each of the antioxidants at 37 degreesC for 1 h, and the b inding for mouse erythrocytes oxidized with ADP-chelated Fe(III) was examin ed. The binding was decreased by preincubation of macrophages with ascorbic acid-related compounds including ascorbic acid, erythorbic acid and dehydr oascorbic acid in a dose-dependent fashion at relatively high concentration s above 10 muM. The binding was similarly decreased by preincubation of mac rophages with catechin compounds including epicatechin, epigallocatechin, e picatechin gallate and epigallocatechin gallate in a dose-dependent fashion at 0.01-100 muM. The binding was more effectively decreased by preincubati on of macrophages with thiol-related compounds including glutathione, oxidi zed glutathione, glutathione Isopropyl ester. and N-acetylcysteine in a dos e dependent fashion at relatively low doses below 1 muM. These results show ed that water-soluble antioxidants especially glutathione and its derivativ es reduced the ability of macrophages to bind oxidized erythrocytes, sugges ting that the activity of lectin-like receptors of macrophages for oxidized erythrocytes was regulated by oxidative mechanisms.