Interaction of ascorbate and alpha-tocopherol enhances antioxidant reserveof erythrocytes during anemia in visceral leishmaniasis

Visceral leishmaniasis (V.L.) is associated with enhanced lipid peroxidatio n along with impaired function of antioxidant defense system in erythrocyte s. The effect of chronic treatment with ascorbate and alpha -tocopherol was studied on erythrocytes in hamsters infected with Leishmania donovani. Com bination treatment with both antioxidants proved to be a potential suppress or of lipid hydroperoxide formation as well as hypotonic osmotic lysis duri ng the leishmanial infection. Positive correlations between the depleted le vels of erythrocyte ascorbate, GSH and alpha -tocopherol exhibit proportion ate alterations in the nonenzymatic antioxidant levels at different stages of infection. Indirect measurement of transmembrane electron transfer as fe rricyanide reduction suggests an active participation of endogenous content s of ascorbate and alpha -tocopherol in the protection against oxidative da mage of membrane lipids. Cooperative behavior of both antioxidants in the f erricyanide reducing capacity was further evinced by resealing the ghosts i n presence of exogenous ascorbate and alpha -tocopherol. Furthermore, intra vesicular ascorbate serves in the defense of extravesicular ferricyanide in duced oxidation of endogenous alpha -tocopherol. The results suggest an int eracting role of ascorbate and alpha -tocopherol in maintaining the antioxi dant reserve of erythrocytes during anemia in V.L. (C) 2000 Elsevier Scienc e Inc. All rights reserved.