Repeated exercise in mice alters expression of IL-10 and TNF-α in intestinal lymphocytes

Intestinal inflammation is characterized by mucosal damage that may arise, in part, to imbalances in pro- and anti-inflammatory cytokines. The purpose of this study was to describe the effects of repeated bouts of strenuous exercise on cytokine expression in mouse intestinal lymphocytes (IL). Thirty-four female C57BL/6 mice were randomly assigned to three groups: three repeated bouts of treadmill running separated by 24 h followed by sacrifice immediately or after a 24 h period or a sedentary (no exercise) control. The pro-inflammatory cytokine, TNF-α, and the anti-inflammatory cytokine, IL-10, were measured in IL by Western blotting. IL-10 concentration increased by 48% (p < 0.05) in the immediate group compared to the sedentary control. TNF-α levels in mouse IL were significantly lower 24 h after completion of the exercise protocol compared to the immediate group (p < 0.05). The results suggest a possible physiological compensation in which intestinal lymphocytes increase the expression of IL-10 in response to exercise-induced stress.