Changes in circulating cytokines and markers of muscle damage in elite cyclists during a multi-stage competition

Summary Correspondence Alfredo Cordova Martinez, DepartamentoBioquimica, Biologia Molecular y Fisiologia, E.U.Fisioterapia - Universidad Valladolid, CampusUniversitario ‘Duques de Soria’, 42004 Soria,SpainE-mail: a.cordova@bio.uva.es Accepted for publication Received 28 January 2014;accepted 28 April 2014 Key words exercise; inflammation; interleukin;malondialdehyde; oxidative stress; tumour necrosisfactor-alpha The purpose of this study was to determine the changes in the basal and post-exercise plasma markers of muscular damage, lipid peroxidation and cytokines ineight male well-trained semiprofessional cyclists, in response to a threeconsecutive-day cycling competition. Serum markers of oxidative and musculardamage – creatine kinase activity, lactate dehydrogenase activity, myoglobin andmalondialdehyde (MDA), creatinine and nitrite levels – followed a sawtooth-typerepresentation throughout the competition. MDA showed an accumulative pattern,evidenced in the post-race values of the third stage which were significantlyhigher with respect to the values of the first stage. Cortisol levels were signifi-cantly influenced by an interaction between the exercise and the stage factors,with higher values on the 4th day. Plasma cytokine levels were only determinedbefore the first stage and post-race, after the third stage. The exercise increasedTNFa, IL6, IL2 and IFNc levels, whereas IL1b was unchanged. In conclusion,cyclist stages induced oxidative and cellular muscle damage which is partiallyrecovered to basal values by the next morning. Repetitive stages during thecycling competition accumulated plasma muscular damage and lipid peroxidationmarkers and pro-inflammatory cytokines, probably as a result of local inflamma-tory responses.