Relationship between oxidative stress and clinical-pathological aspects in dogs experimentally infected with Rangelia vitalii.

The aim of this study was to evaluate lipid peroxidation, protein oxidation and activity of enzymes that are indicators of oxidative stress in Rangelia vitalii infection in dogs. Animals were divided into two groups: negative control (n=5) and infected with R. vitalii (n=7). After inoculation, the parasitemia was estimated daily by microscopic examination of smears. Lipid peroxidation (TBARS) and advanced oxidation protein products (AOPP); and delta-aminolevulinate dehydratase (δ-ALA-D), superoxide dismutase (SOD) and catalase (CAT) activities in blood were evaluated. The samples were collected at days 10 and 20 post-inoculation (PI). TBARS and AOPP levels were higher in the infected group in both analyzed periods (P<0.01). The δ-ALA-D activity was reduced in blood of dogs infected with R. vitalii on days 10 and 20 PI. SOD activity was significantly increased (P<0.01) in the blood of dogs infected with R. vitalii at days 10 and 20 PI, while CAT activity was significantly increased (P<0.01) only at day 20 PI when compared to non-infected animals. A positive correlation was observed between the degree of parasitemia and TBARS and AOPP levels and activity of antioxidant enzymes. The δ-ALA-D activity was negatively correlated with the degree of parasitemia. Based on the increased levels of TBARS, AOPP, SOD and CAT activities, and inhibition δ-ALA-D activity, we concluded that dogs experimentally infected with R. vitalii develop a state of redox unbalance and that these changes might be involved in the pathophysiology of disease.