DNA-DAMAGE AFTER EXHAUSTIVE TREADMILL RUNNING IN TRAINED AND UNTRAINED MEN

The single cell gel electrophoresis (SCG) assay was used to compare th e occurrence of DNA damage in peripheral white blood cells in 6 traine d (TR) and 5 untrained (UT) men after exhaustive exercise. The subject s completed an incremental treadmill test until exhaustion (maximal la ctate: 12.9+/-1.7 in TR and 12.2+/-2.5 mmol . l(-1) in UT). A clear an d significant increase of DNA migration from 2.31+/-0.20 (TR) and 2.22 +/-0.16 (UT) at rest to 2.65+/-0.30 (TR) and 3.00+/-0.41 tail moment ( UT) was found 24 hours after exercise. Noteworthy is that the increase of DNA migration was significantly lower in TR (+ 18.7+/-6.8%) compar ed to UT (+ 35.7+/-8.9%). Plasma levels of malondialdehyde (MDA) were not significantly increased in TR and UT after exercise. At rest and 1 5 minutes after exercise MDA-values were significantly lower in TR com pared to UT, In conclusion the present investigation demonstrates the occurrence of DNA damage in white blood cells following exhaustive exe rcise. This observation may be induced by oxidative stress, Our data s uggest that adaption to training seems to be capable of reducing free radical associated effects, such as DNA damage. Further investigations are needed to clarify the causal mechanisms and biological relevance of exercise-induced DNA damage.