The 8-oxoguanine DNA glycosylase-1 (OGG1) is one of the first lines of defense against 8-oxodg muta- genicity. The mutant hOGG1-Cys326 might be susceptible to a decrease in the repair function for oxidative DNA damage, which leads to higher oxidative DNA damage accumulation with excess oxidative stress. The purpose of this study was to investigate the effects of hOGG1 Ser326Cys polymorphisms on oxidative DNA damage following a single bout of resistance exercise (RE) protocol (7 sets of 4 exercises using 60–90 1 repetition maximum) in the flat pyramid loading pattern. Twenty-eight young resistance-trained men were allocated to two groups according to the hOGG1 gene polymorphism including the wild-type hOGG1-Ser326 genotype (n = 12) and the mutant hOGG1-Cys326 genotype (n = 16). Subjects per- formed a RE protocol (7 sets of 4 exercises using 60–90 1 repetition maximum) in the flat pyramid loading pattern. The hOGG1 genotypes were determined with PCR-RFLP methods at baseline blood samples of each subject. Urine samples taken before, immediately, and 24-h postexercise were analyzed for oxidative DNA damage as measured by urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) excretion. The 8-OH-G levels in the mutant hOGG1-Cys326 geno- type were significantly higher than those in the wild-type hOGG1-Ser326 genotype at pre, post and 24 h post high- intensity RE (p = 0.001, 0.03 and 0.01). Also, significant increase was observed in 8-OHdG level at 24 h post-RE compared with resting values (p = 0.025). Overall, the present study suggests that DNA sequence variations in the hOGG1 gene are associated with the magnitude effects of exercise on oxidative DNA damage in athletes. Genetic variation in the hOGG1 gene plays a role in oxidative stress responses to exercise in athletes. In conclusion, the Ser326Cys genotype in hOGG1 gene was found to be associated with higher oxidative DNA damage following high-intensity RE in athletes. Based on this information, athletes carrying the mutant hOGG1-Cy
