Increased Sensitivity of Aged Erythrocytes to Drugs and Age-Related Loss of Cell Components

抄録

Human erythrocytes were separated into fractions of different age by centrifugation. The effect of some drugs on the separated cells, the levels of some components and enzymes in the cells and the fatty acid composition of membrane phospholipids were estimated to obtain insight into the lifespan of the cells. The bottom (old) cells were relatively more sensitive to the drugs, and aged cells pretreated with chlorpromazine had an increased osmotic fragility and increased viscous properties compared with the top (young) cells, although the differences were relatively small. Significantly lower levels of antioxidant, glutathione and tocopherol, and decreased activities of enzymes (superoxide dismutase, glutathione peroxidase and catalase) involved in peroxide metabolism were observed in old cells as compared with young ones. The proportion of arachidonic acid and the unsaturated/saturated ratio of fatty acids of phospholipids in old cells were significantly lower than those of young cells. The treatment of cells with hydrogen peroxide in vitro produced a dramatic decrease in the proportions of polyenoic fatty acids in all cell fractions, although the decrease in arachidonic acid was less in old cells. The causal relationships among these changes and the lifespan of erythrocytes are discussed.