Denaturation of Erythrocytes by Exposure to photochemically Produced Superoxide Radicals

Abstract

Rat erythrocytes were incubated in the photoactivated riboflavin system, in which the formation of erythrocytes resistant to hypotonic hemolysis occured. Cells illuminated for 60 min were as sensitive to hypotonic hemolysis as unilluminated cells. In contrast, cells illuminated for 120 min showed complete resistance to hypotonic hemolysis. Experiments with catalase, superoxide dismutase and other radical scavengers showed that the formation of protected cells appears to be due to H₂O₂ generated in the photoactivated riboflavin system. Microscopic examination revealed that cells exposed to O₂-for 120 min were enlarged and contained more intensely intracellular materials around the interior periphery. These results suggest that rigid cells resistant to hypotonic hemolysis may be formed by H₂O₂ oxidation of hemoglobin and membrane elements of the cells.