EFFECTS OF INTENSIVE ENDURANCE EXERCISE ON DNA-DAMAGE IN LEUKOCYTES

Objective. It has been shown that highly intensive anaerobic exercise induces DNA damage in leucocytes (LEU), The present study was designed to investigate whether intensive endurance exercise is capable of ind ucing comparable effects, Experimental design, A prospective study. Pa rticipants, Twelve men (aged 27.3+/-4.1 years) who undertook a regular training of different extent (running volume 45+/-5 km week-l) volunt eered in the study. Interventions, The subjects competed in a half mar athon (HM) of 21.1 km, 93.0+/-10.4 min. Measurements. Blood was taken at rest, 1 and 24 hrs after HM for determination of creatine kinase, n eutrophil (PMN), lymphocyte and monocyte counts. DNA damage in LEU at rest and 24 hrs after BM was quantified using the single cell gel-elec trophoresis (SCG) assay. Results. PMN increased from 2.81+/-0.69 to 13 .13+/-2.91 1 hrs after HM (p<0.01) and returned to 3.26+/-0.47 10(9) c ells.l(-1) by 24 hr recovery. DNA migration (image length, IL) reflect ing the extent of DNA damage was elevated significantly in 10 of 12 su bjects one day after HM, IL rose from 32.7+/-2.2 to 40.7+/-3.9 mu m (p <0.01), Correlation analysis revealed a relationship between DNA migra tion 24 hrs after HM and PMN count 1 hr post-exercise (r=0.67, p<0.05) , Conclusions. The results confirm the hypothesis that DNA damage in L EU occurs after intensive endurance exercise. We suppose our observati on of exercise-induced DNA damage in LEU is affected by reactive oxyge n species which are released from PMN, It is quite unclear whether DNA damage in LEU is causal involved in exercise-induced modifications of the immune system.