Oxidative DNA damage in human peripheral leukocytes induced by massive aerobic exercise

Reactive oxygen species produced during vigorous exercise may permeate into cell nuclei and induce oxidative DNA damage, but the supporting evidence i s still lacking. By using a 42 km marathon race as a model of massive aerob ic exercise, we demonstrated a significant degree of unrepaired DNA base ox idation in peripheral immunocompetent cells, despite a concurrent increase in the urinary excretion of 8-hydroxy-2'-deoxyguanosine. Single cell gel el ectrophoresis with the incorporation of lesion-specific endonucleases furth er revealed that oxidized pyrimidines (endonuclease III-sensitive sites) co ntributed to most of the postexercise nucleotide oxidation. The oxidative D NA damage correlated significantly with plasma levels of creatinine kinase and lipid peroxidation metabolites, and lasted for more than 1 week followi ng the race. This phenomenon may be one of the mechanisms behind the immune dysfunctions after exhaustive exercise. (C) 2001 Elsevier Science Inc.