Aerobic exercise affects C57BL/6 murine intestinal contractile function

This study investigated the influence of a moderate exercise training program on the intestinal contractility based on the hypothesis that this organ may endure repetitive periods of ischemia-reperfusion events during moderate aerobic training (10, 25, 40, and 55 days of 60-min treadmill running at 13-21 m/min, 5 days/week). The adaptation of the animal to this program was assessed by significant increase of animal physical performance associated with a mild increase in the wet heart mass-to-body mass ratio. The endurance exercise training caused functional changes of the C57BL/6 ileum contractility, mainly causing a significant reduction of the efficacy of both the electro- (KCl) and pharmacomechanical (acetylcholine, [2-lysine]-angiotensin II, and bradykinin) couplings after 55 days of moderate treadmill running. The level of ileum lipid peroxidation, evaluated by an indirect method, significantly decreased after 10 days of moderate aerobic training, remaining at this lower level throughout the 55 days of training. Altogether, these data demonstrate that the murine ileum is an important target for aerobic moderate exercise training program by causing impairment of the contractility in response to either agonists or depolarization, and that endurance exercise exerts a remarkable protective effect against tissue oxidative stress.