The beneficial effect of L-cysteine supplementation on DNA oxidation induced by forced training.

Background: Forced training is closely implicated with free radicals production and indication of tissue damage as well as DNA oxidation.

Aim: To investigate the effect of L-cysteine (L-cys) supplementation on DNA oxidative damage found in basketball players after forced training.

Subjects And Methods: Blood was obtained from 10 players pre-game (group A), post-game (group B) and after 1 month L-cys (0.5 g 24 h(-1), orally) supplementation, pre- (group C) and post-training (group D). Total antioxidant status (TAS) and the biomarker of DNA oxidative damage 8-hydroxy-2-deoxyguanosine (8-OHdG) as well as creatine kinase (CK) and lactate dehydrogenase (LDH) were measured with commercial kits.

Results: TAS was increased in the groups with L-cys (group C and group D). Post-exercise 8-OHdG levels, CK and LDH were remarkably lower (0.16+/-0.03 ng ml(-1), 115+/-15 U l(-1), 417+/-90 U l(-1), respectively) in group D than those in group B (0.36+/-0.05 ng ml(-1), 286+/-12 U l(-1), 688+/-88U l(-1), p<0.001, respectively). 8-OH dG levels were negatively correlated with TAS(r=-0.718, p<0.01) and positively with CK levels(r=0.590, p<0.01).

Conclusions: L-cys supplementation in basketball players may reduce DNA damage induced by training. The sulfur-containing amino acid may protect muscle cells "death" by increasing TAS and the cellular defense against oxidative stress.