Oxidative process in erythrocytes of individuals with hemoglobin S

Abstract

The understanding of the oxidative stress mechanisms helps to explain many of the processes of cellular lesion and death, especially those related to the hemolytic diseases. Sickle cell anemia, thalassemias and G6-PD deficiency are among the more frequent genetic anomalies accompanied by oxidative stress. In the sickle cells, one of the factors that predisposes to the hemolytic process is the oxidative degradation of the hemoglobin S due to its deoxigenation leading to hemichrome formation and precipitation as Heinz bodies. The oxidative stress contributes to the sickle process and shortening of the erythrocyte survival. Here we analyzed the oxidative process in erythrocytes of patients with two different genotypes for HbS (AS and SS). Units of blood from donors of the Center of Hematology and Hemotherapy of Paraná (HEMEPAR), from normal individuals (AA) and from heterozygote individuals (AS), and venous blood collected from patients with sickle cell anemia (SS) were analyzed. In order to evaluate the protective action of the vitamins C and E in oxidative stress, erythrocytes were treated with antioxidant substances, vitamin C and vitamin E, and then treated with the oxidant tert-butilhydroperoxide (TBHP). The oxidative action induced by TBHP was observed in erythrocytes AA<AS<SS, by the increase in the content of Heinz bodies, methemoglobin, hemolysis, GSH depletion and lowering activities of the enzymes G6-PD and GR. The protective actions of the vitamins C and E for the oxidative stress induced by TBHP were observed for the erythrocytes in the lowering Heinz bodies, methemoglobin, hemolysis, and partial recovery of GSH more efficiently in AS and SS erythrocytes. Recovery was not observed in the levels of the activities of the enzymes G6-PD and GR, under the vitamins actions. The results obtained confirmed the higher susceptibility of the sickle erythrocyte to oxidation which necessitates precaution in the transfusion adequacy of AS erythrocytes. On the other hand, the protective effect of the vitamins C and E over the oxidative stress observed in erythrocytes AS and SS open perspectives for their use for treatment of patients with sickle cell anemias, as well as in the preservation of transfusional erythrocyte bag units.