Increased vulnerability of human erythrocytes to hydroperoxide damage after exposure to cigarette smoke or 1-chloro-2,4-dinitrobenzene in vitro.

Glutathione depletion, a major effect of cigarette smoke on biological tissues exposed to high concentrations of smoke, substantially slowed the consumption of tert-butyl hydroperoxide (tBH) in human erythrocytes in vitro, as shown by electron spin resonance (ESR) analyses of the rate of disappearance of extracellular tBH. Glutathione depletion by the reagent 1-chloro-2,4-dinitrobenzene induced a structural alteration of intracellular hemoglobin by tBH, which was inferred from an increase in hydrophobicity of erythrocyte proteins. Protein hydrophobicity was analyzed with a new ESR assay comprising detection of an increased binding of both anionic and cationic amphiphilic paramagnetic probes in membrane-depleted hemolysates. An increased affinity of oxidant-damaged proteins for amphiphilic probes was also observed in myoglobin and in protein fractions of erythrocytes treated with tBH subsequent to hemolysis. Smoke exposure enhanced the formation of reactive free radicals from tBH by chelated iron and ascorbate. Reactive radical formation, as monitored by spin-trapping methods, was substantially prolonged in erythrocyte suspensions that had been exposed to cigarette smoke. The results of this study suggest that the susceptibility of cells to peroxide-mediated damage, including damage associated with iron-mediated free radical production, is increased after exposure to high concentrations of cigarette smoke.