Oxidative Damage Inflicted by Theileria equi on Horse Erythrocytes When Cultured In Vitro by Microaerophilous Stationary Phase Technique

The aim of present study was to assess the osmotic fragility and oxidative stress in horse erythrocytes infected with Theileria equi in in vitro culture using microaerophilous stationary phase (MASP) technique. Malondialdehyde (MDA) is biomarker of oxidative damage which is indirectly indicative of lipid peroxidation of erythrocytic membrane. The continuous MASP culture of T. equi was established for evaluating the oxidative damage in in vitro condition. Theileria equi-infected erythrocytes (iRBC) were collected from in vitro cultures at different parasitemia (1%-10%). Theileria equi-uninfected erythrocytes (uRBC) were also collected for control studies. Malondialdehyde concentrations in iRBC and uRBC were evaluated. A nonsignificant (P < .001) difference in MDA concentration between uRBC (339.94 ± 0.80 μM/mL) and 1%-10% of iRBC (357.48 ± 0.82 μM/mL) was observed. After 1% of T. equi parasitemia, a sequential significant (P < .001) increase in MDA levels was observed coinciding with increasing T. equi parasitemia. Similarly, osmotic fragility of iRBC also increases with rise in T. equi parasitemia. Percent hemolysis of iRBC increased from 13.89% to 26.40% at 1% to 10% parasitemia in 0.85% of sodium chloride solution. The results of this study demonstrated that horse erythrocytes when infected by T. equi in in vitro condition undergo oxidative damage and osmotic fragility, which increased with increasing parasitic load and may be a contributing factor in pathogenesis process of this disease condition.