Moderate physical exercise protects myenteric metabolically more active neurons in mice infected with Trypanosoma cruzi

Abstract

Background: Trypanosoma cruzi causes neuronal myenteric depopulation compromising intestinal function.

Aim: The purpose of this study was to evaluate the influence of moderate physical exercise on NADH diaphorase (NADH-d)-positive neurons in the myenteric plexus and intestinal wall of the colon in mice infected with T. cruzi.

Materials and methods: Forty 30-day-old male Swiss mice were divided into the following groups: trained infected (TI), sedentary infected (SI), trained control (TC), and sedentary control. The TC and TI groups were subjected to a moderate physical exercise program on a treadmill for 8 weeks. Three days after finishing physical exercise, the TI and SI groups were intraperitoneally inoculated with 1,300 blood trypomastigotes of the Y strain of Trypanosoma cruzi. Parasitemia was evaluated from days 4 to 61 after inoculation. On day 75 of infection, myenteric neurons in the colon were quantified (NADH-d), and inflammatory foci were counted. Tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β) levels were evaluated in plasma. The results were compared using analysis of variance and the Kruskal-Wallis test at a 5 % significance level.

Results: Moderate physical exercise reduced the parasite peak on day 8 of infection (p = 0.0132) and total parasitemia (p = 0.0307). It also prevented neuronal depopulation (p < 0.01), caused hypertrophy of these cells (p < 0.05), prevented the formation of inflammatory foci (p < 0.01), and increased the synthesis of TNF-α (p < 0.01) and TGF-β (p > 0.05).

Conclusion: These results reinforce the therapeutic benefits of moderate physical exercise for T. cruzi infection.