Caroline Felicio Braga

Physical exercise protects myenteric neurons and reduces parasitemia in Trypanosoma cruzi infection.

To evaluate the parasitemia, nitrergic neurons, and cytokines in Trypanosoma cruzi-infected mice subjected to moderate physical exercise, forty male Swiss mice, 30days of age, were divided: Trained Control (TC), Trained Infected (TI), Sedentary Control (SC), and Sedentary Infected (SI). The moderate physical exercise program on a treadmill lasted 8weeks. Three days after completing the moderate physical exercise program, the TI and SI groups were inoculated with 1300 blood trypomastigotes of the Y strain of T. cruzi, and parasitemia was evaluated from day 4 to day 22 after inoculation. After 75days of infection, cytokines were measured and colonic neurons were quantified using immunofluorescence to identify neuronal nitric oxide synthase (nNOS). The results were analyzed using analysis of variance - Tukey and Kruskal-Wallis tests, to 5% significance. Moderate physical exercise reduced the parasite peak on day 8 of infection and total parasitemia (p<0.05), contributed to survival of number of nNOS-immunoreactive neurons (p<0.01) and promoted neuronal hypertrophy of the neurons (p<0.05), increased the synthesis of tumor necrosis factor-α (p<0.01) and transforming growth factor-β (p>0.05), providing beneficial effects to the host by acting on the immune system to preserve nitrergic neurons.