Eur J Appl Physiol (1994) 68:48-53 ,u,o,.. A p p l i e d Journal of Physiology and Occupational Physiology © Springer-Verlag 1994 Do invading leucocytes contribute to the decrease in glutathione concentrations indicating oxidative stress in exercised muscle, or are they important for its recovery? J. A. Duarte 1, F. Carvalho 2, M. L. Bastos 2, J. M. C. Soares 1, H.-J. Appell 3 1 Department of Sports Biology, Faculty of Sport Sciences, University of Porto, Portugal 2 Department of Toxicology, Faculty of Pharmacy, University of Porto, Portugal 3 Institute for Experimental Morphology, German Sport University, D-50927 Cologne, Germany Accepted September 24, 1993 Abstract. Mice were subjected to one session of stre- nuous running exercise and their soleus muscles were examined in respect of changes in ultrastructure and to their concentration of reduced glutathione [GSH] which are indicators of oxidative stress. It was hypo- thesized that invading leucocytes contributed to oxida- tive stress and they were functionally inhibited in one experimental group by the administration of colchi- cine. Exercise led to an immediate decrease in [GSH] of about 60%, which slowly recovered during 96 h after exercise. With the administration of colchicine after exercise, [GSH] was higher than in the untreated exer- cise group 48 h after exercise, indicating an inhibition of the ability of leucocytes to produce oxidative stress. However, at 96 h after exercise, [GSH] was lower in the treated exercise group than in the untreated group. The morphological evaluation of the percentage of af- fected fibres showed that the invasion of leucocytes in- creased muscle fibre damage. The results suggested that invading leucocytes enhanced production of reac- tive species of oxygen that may have participated in in- ducing muscle damage. However, inhibition of leuco- cyte invasion did not permit their scavenger action of removing cell debris, which appeared to produce even more oxidative stress in the muscle. Key words: Skeletal muscle - Exercise - Leucocyte in- vasion - Oxidative stress - Glutathione - Colchicine Introduction There is increasing evidence that has indicated that reactive species of oxygen (RSO) are important media- tors in inducing multiple forms of cell damage (Laugh- lin et al. 1990; Ferrari et al. 1991). Skeletal muscle damage has been described after intense and/or ex- hausting exercise (Appell et al. 1992). The participa- Correspondence to: H.-J. Appell tion of RSO in inducing such damage has been sug- gested by studies that have described a decrease in concentrations of reduced glutathione [GSH] and an increase in oxidated glutathione concentrations [GSSG] immediately after exercise (Lew et al. 1985, 1987; Quintanilha 1988). Other studies have reported variations in the activity of some enzymes involved in protection against oxidative stress (Salminen and Vih- ko 1983a, b; Alessio and Goldfarb 1988) and have found indirect markers for lipid peroxidation in muscle (Lew et al. 1987; Starnes et al. 1989) after exercise. These and other (Salminen/985) biochemical alter- ations observed in homogenized muscle tissue may have originated either from resident cells in skeletal muscle or from an inflammatory response, particularly by invading leucocytes (Evans and Cannon 1991) which has been found in skeletal muscle after stre- nuous exercise (Kuipers et al. 1983; Armstrong 1990; Evans and Cannon 1991). Neutrophils and macro- phages have been found to represent a potential source for RSO (Weiss 1986; Henson and Johnston 1987; Cochrane 1991; Dargel 1992). Considering the cytotoxic effects of RSO and of other components lib- erated by leucocytes (Henson and Johnston 1987), it is possible that leucocytes contribute not only to the afor- ementioned biochemical alterations indicative of oxi- dative stress but also play a role in the development of structural abnormalities (Armstrong 1990; Evans and Cannon 1991; Appell et al. 1992). The tissue [GSH] has been shown to represent a sensitive indicator of the equilibrium between produc- tion and removal of RSO (Reed 1990; Uhlig and Wen- del 1992). If migrating leucocytes, especially neutro- phils and monocytes/macrophages, contribute substan- tially to oxidative stress in skeletal muscle, the use of colchicine as a potent inhibitor of various leucocyte functions (locomotion, chemotaxis, adhesiveness, ly- sosomal degranulation; Wallace et al. 1970) should be accompanied by concomitant [GSH] changes in exer- cised muscle. Similarly, the use of colchicine may atte- nuate the structural changes presumably induced by leucocytes.