Water-soluble antioxidant specificity against free radical injury using cultured human ventricular myocytes and fibroblasts and saphenous vein endothelial cells.

To better understand the protective effect of water-soluble antioxidants against free radical injury to the reperfused ischemic myocardium, we studied the antioxidant effectiveness of superoxide dismutase (SOD), catalase, ascorbic acid, and Trolox, a water-soluble analogue of alpha-tocopherol, in protecting cultured adult human ventricular myocytes and fibroblasts and saphenous vein endothelial cells from hypoxanthine-xanthine oxidase generated free radicals. The cells were cultured at oxygen tension to 150 and 40 mmHg. Passage P2 to P4 cells were injured by a hypoxanthine-xanthine oxidase free radical generation system. The time when all the cells became shriveled divided by the cell count expressed in terms of 100,000 cells was used to compare cellular susceptibilities to free radical injury and the relative effectiveness of the antioxidants. Fibroblasts were more resistant to free radical injury than myocytes which were more resistant than endothelial cells, when all three cell types were cultured at the same oxygen tension. Trolox and ascorbic acid were effective antioxidants for myocytes while SOD and catalase were ineffective. SOD and catalase were more effective than ascorbic acid as antioxidants for endothelial cells and fibroblasts, while Trolox was ineffective. In summary, we have shown that each cultured cell type has a different susceptibility to free radical damage and that antioxidants are not effective for all cell types.