Increased lipid peroxidation of erythrocytes in blood stored in polyvinyl chloride blood storage bags plasticized with di-[2-ethyl hexyl] phthalate and effect of antioxidants.

BACKGROUND AND OBJECTIVES

Previous work in this laboratory has shown significant decrease in vitamin E in erythrocytes in blood stored in polyvinyl chloride (PVC) bags plasticized with di-[2-ethyl hexyl] phthalate (DEHP), and in erythrocytes incubated in vitro with DEHP. Since vitamin E is a major antioxidant, a study was carried out to find out whether this decrease observed in vitamin E has an effect on lipid peroxidation in blood stored in DEHP-plasticized PVC blood bags.

MATERIALS AND METHODS

Blood was collected in Penpol blood storage bags (which is a DEHP-plasticized PVC bag) and parameters of lipid peroxidation, i.e. activity of superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione reductase, concentration of malondialdehyde (MDA), conjugated dienes, hydroperoxides, glutathione and vitamin E studied in erythrocytes after various periods of storage as compared to glass bottles. Erythrocytes were also incubated in vitro with DEHP with and without vitamin E, and changes in lipid peroxidation studied.

RESULTS

Blood stored in Penpol bags showed increased lipid peroxidation in erythrocytes as compared to that stored in glass bottles, as is evident from a greater increase in MDA and a greater decrease in glutathione and a significant decrease in vitamin E. The addition of vitamin E decreased the formation of MDA and conjugated dienes and prevented the decrease in vitamin E. However in spite of increased lipid peroxidation in the presence of DEHP, the release of K+ and hemoglobin from erythrocytes was lower. When there was an increase in DEHP taken up by erythrocytes, there was a corresponding decrease in vitamin E. More important, whenever there was an increase in vitamin E in erythrocytes (when RBCs in the presence of DEHP were incubated with vitamin E), there was a progressive decrease in DEHP.

CONCLUSION

DEHP caused increased lipid peroxidation in erythrocytes. At the same time, it decreased the release of K+ and hemoglobin from erythrocytes. It is possible that the stabilizing effect of DEHP on the erythrocyte membrane may offset the detrimental effects of the increased lipid peroxidation it causes.