Parasite control and skeletal myositis in Trypanosoma cruzi-infected and exercised rats.

Abstract

Non-pharmacological strategies have been rarely described in the treatment of infectious diseases.Although exercise training has been recently incorporated in the clinical management of Chagas disease,the rationale basis that supports this indication is poorly understood. Thus, we investigated the effectof an aerobic exercise on the parasitism, inflammation and oxidative tissue damage in a murine modelof Trypanosoma cruzi-induced skeletal myositis. Wistar rats were randomized into four groups: trainednot infected (TNI) and infected (TI), sedentary not infected (SNI) and infected (SI). A running trainingprogram was administered 5 days/week for 9 weeks. Then, infected animals were inoculated with T. cruziand followed up for another 9 weeks. Exercise training induced beneficial adaptations by increasing timeto fatigue and lactate threshold in TNI and TI animals. SI animals presented higher parasitemia, skele-tal muscle parasitism, cell necrosis, leukocyte infiltration, cytokines levels, reactive oxygen species andnitric oxide production, thiobarbituric acid reactive substances, carbonyl proteins, myosin heavy chain Idepletion, and increased catalase (CAT) and superoxide dismutase (SOD) activities. Beyond attenuationin all these variables, TI animals showed reduced TNF- , CCL-2/MCP-1 and CX3CL1, and increased IL-10muscle levels. Furthermore, these animals presented higher CAT and SOD activities and reduced lipidand protein oxidation. Taken together, our findings indicated that exercise training induced a protectivephenotype in T. cruzi-infected mice, enhancing host defenses against the parasite and attenuating thepathological remodeling associated with skeletal myositis, aspects potentially associated to an improvedimmunological and redox balance in infected animals.