OXIDATIVE DAMAGE AND ENHANCED ERYTHROPHAGOCYTOSIS IN CANINE ERYTHROCYTES INFECTED WITH BABESIA-GIBSONI

Oxidative damage to canine erythrocytes infected with Babesia gibsoni was investigated. B. gibsoni was cultured together with erythrocytes f rom normal dogs. When parasitemia reached a peak level, concentrations of both methemoglobin (metHb) and malondialdehyde (MDA), an end produ ct of lipid peroxidation, in erythrocytes were significantly higher th an at cultivation Day 0. In addition, B. gibsoni-infected dogs with hi gh parasitemia showed significant increases of both metHb and MDA conc entrations in erythrocytes compared to those in uninfected dogs. Furth ermore, erythrocytes from parasitized culture were more susceptible to phagocytosis by bone marrow macrophages from normal dogs than erythro cytes from the control culture. In addition, macrophages ingested not only parasitized erythrocytes but also non-parasitized cells. These re sults suggested that oxidative damage to erythrocytes was induced by t he multiplication of B. gibsoni, and that non-parasitized erythrocytes were also exposed to oxidative stress during the infection by B. gibs oni.