Potassium superoxide induction of rabbit corneal endothelial cell damage

Rabbit corneal endothelial cells were perfused with a Krebs Ringer bicarbonate solution to which potassium superoxide had been added. Concentrations of potassium superoxide of 0.5 mM and higher resulted in severe anatomic and physiologic alteration of endothelial cells that resulted in corneal swelling. Catalase offered protection whereas the toxic effect was unaltered by superoxide dismutase, ascorbic acid, DETAPAC, EDTA, EDTA-FeC1(20, or DMSO. The data suggests that hydrogen peroxide is the toxic species and that superoxide anion and hydroxyl free radical are either not toxic in this system or are at such low concentrations that cell damage does not occur. The role of singlet oxygen cannot be defined, but its participation appears unlikely. Endothelial intracellular glutathione levels and redox state were unaffected by perfusion with a solution to which 0.3 mM potassium superoxide had been added.