Membrane effects of nitrite-induced oxidation of human red blood cells

The aim of our investigation was to study the red blood cell (RBC) membrane effects of NaNO2-induced oxidative stress. Hyperpolarization of erythrocyt e membranes and an increase in membrane rigidity have been shown as a resul t of RBC oxidation by sodium nitrite. These membrane changes preceded reduc ed glutathione depletion and were observed simultaneously with methemoglobi n (metHb) formation. Changes of the glutathione pool (total and reduced glu tathione, and mixed protein-glutathione disulfides) during nitrite-induced erythrocyte oxidation have been demonstrated. The rates of intracellular ox yhemoglobin and GSH oxidation highly increased as pH decreased in the range of 7.5-6.5. The activation energy of intracellular metHb formation obtaine d from the temperature dependence of the rate of HbO(2) oxidation in RBC wa s equal to 16.7 +/- 1.6 kJ/mol in comparison with 12.8 +/- 1.5 kJ/mol calcu lated for metHb formation in hemolysates. It was found that anion exchange protein (band 3 protein) of the erythrocyte membrane does not participate s ignificantly in the transport of nitrite ions into the erythrocytes as band 3 inhibitors (DIDS, SITS) did not decrease the intracellular HbO(2) oxidat ion by extracellular nitrite. (C) 1999 Elsevier Science B.V. All rights res erved.