The Human 8-oxoG DNA Glycosylase 1 () 326 Polymorphism in Infertile Men.

BACKGROUND/OBJECTIVES: 8-hydroxy-2'-deoxyguanosine (8-OHdG) is a form of oxidative DNA damage caused by oxidative stress (OS), which is considered a major factor in male infertility. The cellular defense system against 8-OHdG involves base excision repair (BER) with the enzyme 8-Oxoguanine DNA glycosylase 1 (OGG1). However, studies on the single-nucleotide polymorphism (SNP) OGG1 326 have demonstrated that the 326 genotype could be the cause of an increment in oxidative DNA damage. In this study, the OGG1 326 polymorphism and its effect on DNA oxidation were evaluated in 118 infertile men.

METHODS

Polymorphic screening was performed using TaqMan allelic discrimination assays, and oxidative DNA damage was evaluated through the quantification of 8-OHdG and total antioxidant capacity (TAC); in addition, electrical bioimpedance spectroscopy (EBiS) measurements were used as a reference for different electrical properties associated with 8-OHdG concentrations.

RESULTS

The detected (G) allele frequency (0.4) was higher compared to the allele frequency reported in the "Allele Frequency Aggregator" (ALFA) and "Haplotype Map" (HapMap) projects for American populations (0.21-0.29), suggesting that the (G) allele carrier could be a factor associated with American infertile populations. The values of 8-OHdG were twofold higher in carriers of the 326 (GG) genotype than the other genotypes and, in concordance, the TAC levels were threefold lower in 326 (GG) genotype carriers compared to the other genotypes. Moreover, the EBiS magnitude exhibited potential for the detection of different oxidative damage in DNA samples between genotypes.

CONCLUSIONS

The 326 (GG) genotype is associated with oxidative DNA damage that could contribute to male infertility.