Evaluation of oxidative/nitrosative stress biomarkers and DNA damage in buffaloes naturally infected with Theileria annulata.

Previously, we evaluated serum sialic acid (SA) levels in buffaloes naturally infected with T. annulata. In the current paper, we conducted a further study on oxidative/nitrosative stress biomarkers in erythrocyte lysate samples of the same buffaloes. DNA damage also was assessed. Additionally, we tested whether, there is any correlation between SA and the aforementioned indicators or not. To achieve these aims, several biomarkers including the activities of key antioxidant enzymes, superoxide dismutase, glutathione peroxidase and catalase, as well as malondialdehyde (MDA), protein carbonyl (PCO), nitric oxide contents (NO), total antioxidant capacity (TAC) and DNA damage levels were measured. The obtained results showed that the activities of the antioxidant enzymes and TAC levels decreased significantly as the percentage of parasitemia increased accordingly. Also, a significant increase in the levels of PCO, MDA, NO and DNA damage were recorded, depending on the degree of parasitemia. There was a significant correlation between oxidative/nitrosative stress indicators and SA. Conclusively, T. annulata infection in buffaloes is associated with a parasitic burden-dependent oxidative/nitrosative damages to erythrocytes and SA plays a crucial role in pathogenesis of the disease, as it is tightly correlated with oxidative/nitrosative indicators.