Peroxide-induced membrane damage in human erythrocytes

Erythrocytes exposed to H2O2 or t-butyl hydroperoxide (tBHP) exhibited lipid peroxidation and increased passive cation permeability. In the case of tBHP a virtually complete inhibition of both processes was caused by butylated hydroxytoluene (BHT), whereas pretreatment of the cells with CO increased both lipid peroxidation and K+ leakage. In the experiments with H2O2, on the other hand, both BHT and CO strongly inhibited lipid peroxidation, without affecting the increased passive cation permeability. These observations indicate different mechanisms of oxidative damage, induced by H2O2 and tBHP, respectively. The SH-reagent diamide strongly inhibited H2O2-induced K+ leakage, indicating the involvement of SH oxidation in this process. With tBHP, on the contrary, K+ leakage was not significantly influenced by diamide. Thiourea inhibited tBHP-induced K+ leakage, without affecting lipid peroxidation. Together with other experimental evidence this contradicts a rigorous interdependence of tBHP-induced lipid peroxidation and K+ leakage.