Nitric oxide level, protein oxidation and antioxidant enzymes in rats infected by Trypanosoma evansi

Infection with T. evansi in rats caused an increased nitric oxide and advanced oxidation protein products levels in serum and antioxidant enzyme in total blood. [Display omitted] ► Trypanosoma evansi is the causative agent of an important disease that affects a wide variety of domestic and wild mammals. ► Nitric oxide has many physiological effects in body animals and human. ► NO level in serum, indicated by nitrite/nitrate concentration, was higher in infected rats with T. evansi. ► Serum AOPP level was higher in infected rats by parasite, i.e. protein oxidation. ► An increase in antioxidant enzyme activity occur in infection by T. evansi caused by oxidative damage. The aim of this study was to evaluate the nitric oxide (NO) level, protein oxidation and antioxidant enzymes in rats infected with Trypanosoma evansi and establish the association of NO levels with the degree of parasitemia. Thirty-six male rats (Wistar) were divided into two groups with 18 animals each. Group A was not infected while Group B was intraperitoneally infected, receiving 7.5×106 trypomastigotes per animal. Each group was divided into three subgroups with 6 rats each and blood was collected during different periods post-infection (PI), as follows: day 5 (A5 and B5), day 15 (A15 and B15) and day 30 PI (A30 and B30). Blood samples were collected by cardiac puncture to estimate the levels of nitrites/nitrates (NOx) and advanced oxidation protein products (AOPP) in serum, and superoxide dismutase (SOD) and catalase (CAT) activities in blood. On days 15 and 30 PI NOx and AOPP levels were increased in serum of rats infected. Rodents infected with T. evansi showed a significant increase in SOD (days 5 and 15 PI) and CAT (day 30 PI) activities. Based on the physiological role of NO, we can conclude that its increased concentration is related to an inflammatory response against the parasite, once a redox imbalance was observed during infection.