Estudo do papel das espécies reativas de oxigênio (ROS) na resposta inflamatória induzida pelo exercício físico em camundongos

Abstract

During an acute bout of exercise there is an activation and mobilization of immune cells into circulation. These cells may infiltrate into muscle sites inducing local inflammatory response. Skeletal muscle has many sources of reactive oxygen species (ROS) that are activated during and after exercise. These factors indicate changes in biologic redox state and onset of an inflammatory process in response to exercise. Nevertheless, the role of ROS in an inflammatory response immediately and hours after an exercise bout is not elucidated. PURPOSE: The aim of this study is, thus, to investigate the role of ROS in an inflammatory response in mice running to fatigue. METHODS: C57/BL6, LysM-eGFP and gp91phox-/- animals performed exercise to fatigue on a treadmill. Blood, muscle and intravital images from the muscle tissue were collected after exercise at different time-points. Leukocyte recruitment was assessed by intravital microscopy and histological technical. RESULTS: There was an enhancement in plasma lactate and CK concentration after exercise. Total number of cells in the blood increased 12 and 24h after exercise when compared with control group. The number of blood monocytes, neutrophils and lymphocytes also increased 12 and 24h post-exercise. There was a raise in leukocyte rolling compared to basal levels at 3, 6, 12 and 24h post-exercise. In the exercising group Adhesion cells and transmigrating cells were increased 6 and 12h post-exercise, respectively Apocynin administration completely inhibited cell recruitment and SOD exacerbated the increase of number of adherent cells 12h more than exercise group. The magnitude of workload (60% of intensity or 60% of duration) did not change the number of rolling and adherent cells. CK levels increased less in a lower magnitude of workload. Physical training does not inhibit the increase in blood CK levels and in the number of rolling and adherent leukocytes in a post capillary venule. The expression of adhesion molecules as L-selectin, P-selectin and PECAM-1 increases 12h after exercise and apocynin can block this response. Training protocol also increased the expression of L-selectin, E-selectin and Pax3. CONCLUSION: These findings suggest that exercise to fatigue leads to a cross-talk between immune system and muscular tissue in a ROS-dependent manner.