DO INVADING LEUKOCYTES CONTRIBUTE TO THE DECREASE IN GLUTATHIONE CONCENTRATIONS INDICATING OXIDATIVE STRESS IN EXERCISED MUSCLE, OR ARE THEY IMPORTANT FOR ITS RECOVERY

Mice were subjected to one session of strenuous running exercise and t heir soleus muscles were examined in respect of changes in ultrastruct ure and to their concentration of reduced glutathione [GSH] which are indicators of oxidative stress. It was hypothesized that invading leuc ocytes contributed to oxidative stress and they were functionally inhi bited in one experimental group by the administration of colchicine. E xercise led to an immediate decrease in [GSH] of about 60%, which slow ly recovered during 96 h after exercise. With the administration of co lchicine after exercise, [GSH] was higher than in the untreated exerci se group 48 h after exercise, indicating an inhibition of the ability of leucocytes to produce oxidative stress. However, at 96 h after exer cise, [GSH] was lower in the treated exercise group than in the untrea ted group. The morphological evaluation of the percentage of affected fibres showed that the invasion of leucocytes in creased muscle fibre damage. The results suggested that invading leucocytes enhanced produc tion of reactive species of oxygen that may have participated in induc ing muscle damage. However, inhibition of leucocyte invasion did not p ermit their scavenger action of removing cell debris, which appeared t o produce even more oxidative stress in the muscle.