The microphotohemolytic response of erythrocytes is altered by streptozotocin-induced diabetes and copper deficiency in rats.

Microphotohemolysis is a new technique that has been used to determine the presence of alterations in the erythrocyte membrane. The method involves light activation through a microscope of a fluorescent dye-erythrocyte-buffer solution in a hemocytometer. The interaction of the light and dye result in the generation of toxic oxygen products which attack the membrane allowing water to enter the cell. As hemolysis occurs the optical density of the microscopic field decreases and this is recorded for later quantitation with an image analysis system. Maximal effect, time to half maximal effect and the slope of the hemolysis curve are determined. The goal of this study was to determine if microphotohemolysis could be used to detect differences in erythrocytes from animals with altered physiological states such as hypercholesterolemia, diabetes, and copper deficiency. These are conditions that alter the lipid or protein structure of the erythrocyte membrane and/or the antioxidative capacity of the erythrocyte. There were no effects of hypercholesterolemia on the microphotohemolytic response of the erythrocyte. Streptozotocin-induced diabetes resulted in a decreased maximum effect, a significant shift of the hemolysis curve to the right (increased T 1/2) and a significant decrease in the slope of the hemolysis curve. Copper deficiency resulted in a significant decrease in the slope of the hemolysis curve. These results in diabetes and copper deficiency are consistent with an altered protein structure in the erythrocyte membrane that occurs in these conditions. The data demonstrate that this technique may be used to detect differences between normal and altered erythrocytes. As such, it could be useful in monitoring the course of a disease or its treatment.