Glutathione oxidation and biophysical aspects of injury to human erythrocytes

Biophysical studies were made on human erythrocytes in which glutathione (GSH) had been oxidized by methyl phenyldiazenecarboxylate (azoester). (1) No differences from the normal were observed when the red blood cells were not depleted of most of their GSH. (2) Chemical challenge provided by the reagent when used in excess of that required to oxidize GSH resulted in injury to erythrocytes. (3) Excess azoester generates reactive species via hydrolysis in the presence of oxygen, and under different, but easily controlled, experimental conditions 2 distinct patterns of injury to the red cell could be observed: (a) intracellular denaturation of protein, leading to the appearance of electron-dense masses, with only a mild effect on the membrane, as demonstrated by diminution in surface charge; (b) severe, ultrastructurally demonstrable membrane damage, accompanied by diminished cell density and increased osmotic fragility, but without significant denaturation of intracellular protein. (4) These patterns of damage to cell and membrane were achieved by treatment with excess azoester of erythrocytes containing oxyhemoglobin (pattern a) and carbon monoxyhemoglobin (pattern b), respectively, in an oxygenated environment. These two modes of treating the human red blood cell with agents of well-defined chemistry are models for the damage produced by certain drugs and metabolites. After deprivation of much of the intracellular GSH, the further consequences of certain challenges, intracellular or membrane damage, would lead to either sequestration or intravascular lysis.