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 from normal dogs. When parasitemia reached a peak level, concentrations of both methemoglobin (metHb) and malondialdehyde (MDA), an end product of lipid peroxidation, in erythrocytes were significantly higher than at cultivation Day 0. In addition, B. gibsoni-infected dogs with high parasitemia showed significant increases of both metHb and MDA concentration in erythrocytes compared to those in uninfected dogs. Furthermore, erythrocytes from parasitized culture were more susceptible to phagocytosis by bone marrow macrophages from normal dogs than erythrocytes from the control culture. In addition, macrophages ingested not only parasitized erythrocytes but also non-parasitized cells. These results suggested that oxidative damage to erythrocytes was induced by the multiplications of B. gibsoni, and that non-parasitized erythrocytes were also exposed erythrocytes oxidative stress during the infection by B. gibsoni.