Preinfection aerobic treadmill training improves resistance against Trypanosoma cruzi infection in mice.

Exercise performed before infections has been linked to improvement of the immune response against infections. The purpose of this study was to evaluate the influence of preinfection moderate-intensity treadmill training on acute Trypanosoma cruzi infection in mice. Ninety-nine female BALB/c mice were divided into 4 groups, as follows: training + infection (T+I) (n = 41); no training + infection (NT+I) (n = 38); training + no infection (T+NI) (n = 10); and no training + no infection (NT+NI) (n = 10). The exercise program for trained groups was carried out on a motorized treadmill for 8 weeks. Infected groups were inoculated with the Y strain of T. cruzi. Infectivity, prepatent period, patent period, parasitemia peak, mortality, survival time, weight, food intake, tumor necrosis factor-alpha serum levels, and peritoneal macrophage hydrogen peroxide production were evaluated. We found that preinfection training induced statistically significant reductions in parasitemia peak (p < 0.03) and weight loss (p < 0.04). However, no statistically significant differences were found for the other parameters evaluated when trained and nontrained infected groups were compared. We conclude that preinfection aerobic training induces some improvement in the immune response to T. cruzi infection in female BALB/c mice.