Increased Generation of Superoxide in Erythrocytes infected with Babesia gibsoni.

Abstract

ABSTRACT. The present study was conducted to clarify the mechanism underlying the oxidative process in erythrocytes infected with Babesia gibsoni. The parasite B. gibsoni was cultured together with erythrocytes from normal dogs for 7 days. When parasitemia reached 12.0-13.4% at Day 7, the production of superoxide in erythrocytes was significantly higher in the parasitized culture than in the control culture (p<0.005). The concentration of thiobarbituric acid reactive substances (TBARS) in erythrocytes in parasitized culture was also significantly increased compared with the control culture (p<0.005), indicating that lipid peroxidation was greater in infected erythrocytes than in non-infected cells. In addition, the rates of superoxide generation in the blood of B. gibsoni-infected dogs were also significantly higher than in non-infected dogs (p<0.001). These results indicate that superoxide anions are increased in erythrocytes parasitized with B. gibsoni, and suggest that oxidative damage, due to lipid peroxidation, might be caused in host erythrocytes by the parasite. KEY WORDS: Babesia gibsoni, oxidative damage, superoxide.J. Vet. Med. Sci. 63(10): 1077-1081, 2001 Babesia spp. are well-known blood parasites that cause severe hemolytic anemia in domestic animals [4]. In general, Babesia parasites, as well as Theileria and malaria parasites, invade erythrocytes of infected animals, which results in the destruction of the parasitized erythrocytes [3]. However, severe anemia often occurs in animals infected with this parasite in spite of a low percentage of parasitized erythrocytes in their peripheral blood [4,9]. This phenomenon suggests the possibility of non-parasitized erythrocytes also being damaged due to the parasite infection, resulting in enhanced erythrocyte destruction. We previously reported that concentrations of both methemoglobin and malondialdehyde (MDA), an end product of lipid peroxidation, increase in erythrocytes cultured with B. gibsoni, and that B. gibsoni-infected dogs with high parasitemia also show significant increases of both methemoglobin and MDA in erythrocytes compared with those in non-infected dogs [10]. These results indicate that oxidative damage to erythrocytes is induced by B. gibsoni infection and suggest that active oxygen might be generated by the multiplication of the parasites. Furthermore, erythrocytes cultured with B. gibsoni are more susceptible to phagocytosis by bone marrow macrophages from normal dogs than erythrocytes cultured without B. gibsoni. In addition, 89 percent of erythrocytes phagocytized by macrophages were non-parasitized erythrocytes [10]. However, it has not been clarified whether the Babesia parasite is able to generate reactive oxygen species. The present study was carried out to elucidate the mechanisms underlying the oxidative process in erythrocytes infected with B. gibsoni. MATERIALS AND METHODSThree dogs were inoculated with B. gibsoni-infected blood from other carrier dogs, and used as B. gibsoniinfected dogs in the present study. Five normal do...

Inhibitory Effect of Pyrimidine and Purine Nucleotides on the Multiplication of <i>Babesia gibsoni</i>: Possible Cause of Low Parasitemia and Simultaneous Reticulocytosis in Canine Babesiosis

“…This result obtained from the in vivo investigation does not seem to be consistent with the results from in vitro examinations in the present and previous studies [7]. It is known that many enzyme activities in erythrocytes of dogs infected with B. gibsoni are significantly higher than those of noninfected dogs because of the high percentage of reticulocytes in infected dogs [16]. The erythrocyte 5'-nucleotidase activity in infected dogs was approximately proportional to the percentage of reticulocytes in each individual in the present study.…”

“…6). As mentioned above, the low parasitemia in vivo may be the result of some immunological and biochemical activities, i.e., the protective effect of parasitespecific antibodies, toxicity of free radicals [13,15,16], increased phagocytic activity of macrophages [12], and so on. The decreased activity of erythrocyte 5'-nucleotidase and subsequent accumulation of nucleotides might also contribute in part to the low parasitemia in vivo.…”

Status of lipid peroxidation and antioxidant enzymes in goats naturally infected with Babesia ovis

“…Therefore, the increased production of these free radicals leads to augmented oxidative stress to macromolecules and biomembranes, resulting in enhanced lipid peroxidation and MDA production (Saleh 2009). The high concentration of lipid peroxides from dogs with babesiosis can probably be ascribed to multiplications of B. gibsoni (Otsuko et al 2001, Kumar et al 2006. However, high level of MDA concentration in B. canis-infected dogs could be related to enhanced lipid peroxidation and also because of decreased kidney function (Crnogaj et al 2010).…”

“…Although, the mechanism of increased activity of SOD in infected erythrocytes cannot be explained explicity, it is likely that up-regulation of the synthesis of SOD is driven by the body's homeostatic mechanisms to counter oxidative damage due to parasitemia and multiplication of parasites inside the cells (Chiwakata et al 2000, Chaudhuri et al 2008. It may be associated with a high percentage of reticulocytes in the infected dogs because the activity of enzymes is higher in reticulocytes compared with mature erythrocytes (Yamasaki et al 2000, Otsuko et al 2001.…”

“…It is markedly increased at the onset of anemia in natural B. bigemina infections and an inverse relationship has been observed between methemoglobin levels and the PCV (Saleh 2009). In B. gibsoni infections, there is strong evidence of the role of erythrocyte oxidation *Corresponding author: mtavassoli2000@yahoo.com Evaluation of antioxidant status and oxidative stress in goats infected with B. ovis 229 (as indicated by lipid peroxidation, hemoglobin oxidation and increased osmotic fragility of erythrocytes) in the pathogenesis of anemia observed in infected dogs (Otsuko et al 2001, Kumar et al 2006, Chaudhuri et al 2008.…”