O exercício físico crónico altera o perfil leucocitário e a taxa de fagocitose de ratos estressados

Abstract

Moderate physical exercise may be beneficial for immune system, unlike a stress state. The present study intended to verify if a chronic physical exercise performed before a stress state can change the blood leukocyte profile and the phagocytic function of alveolar macrophages. Male Wistar rats (n=61) were assigned to 4 groups: non-exercised (NE), non-exercised plus stress (NE+S), exercised (E) and exercised plus stress (E+S). The exercised groups (E and E+S) were submitted to swimming exercise during six weeks (45 min/day, 5 days p/week and overload until 3% of body weight). The stress groups (NE+S and E+S) were submitted to an acute restrain stress (40 min) 24 hours after the last bout of exercise. The blood red series were not altered in all studied groups. However, when compared to NE group, the non- exercised animals submitted to stress showed a decrease in the total number of leukocytes with a reduced number of lymphocytes and an increase in neutrophil count. These alterations were not observed in exercised animals (E+S). The phagocytic ratio of macrophages increased in E group and did not show any decrease in E+S group. Our results suggest that physical exercise performed during six weeks attenuates the stress-induced alterations in the leukocyte profile and enhances the phagocytic function of macrophages. More studies are nec- essary to evaluate the clinical significance and the mechanism of such alterations.