Exercício físico regular diminui o estresse oxidativo pulmonar em ratos após exposi??o aguda ao carv?o mineral

摘要

Several studies have pointed the regular low to moderate intensity physical exercise an important agent to combat the oxidant stress. The purpose of this study was to investigate the effect of the physical exercise in the pulmonary oxidant response after inhaling mineral coal dust. Twenty-four male Wistar rats (200-250 g) were randomly divided in two groups with their respective controls (trained, n = 6; non-trained, n = 6). All animals received mineral coal dust via tracheal instillation (saline 3 mg/0.5 ml, 3 days/week for 3 weeks), or 0.5 ml of 0.9% saline solution. Forty-eight hours after the last instillation, the trained group was submitted to a progressive exercise program on treadmill for twelve weeks (up to 17 m.min-1, 50 min/day-1, 10% inclination). Forty-eight hours after the last training session, every animal was killed by decapitation, and their lungs and soleus were surgically removed for later biochemical analysis. The citrate synthase activity was determined in the soleus muscle, and the damages on the lipids and proteins were assessed into the lungs by means of the TBARS concentration and by determining the carbonyl groups, respectively. The results show that the regular practice of physical exercises reduces significantly the present TBARS levels in trained rats, decreasing the oxidation levels in proteins of both groups compared to their respective controls. The results lead us to suggest that the regular physical exercise on treadmill is an agent capable to soften the pulmonary oxidant damages caused by inhaling mineral coal particles.