Influence of Val16Ala-SOD2 polymorphism on sperm quality parameters.

The purpose of this study was to investigate the association between the Val16Ala superoxide dismutase manganese-dependent (SOD2) single nucleotide polymorphism (SNP) and sperm reproductive parameters in a sample of Brazilian men. A potential association between this polymorphism and some oxidative biochemical parameters as well as sperm plasma cell-free DNA (cfDNA) levels were also evaluated. The study was performed using semen samples obtained from male patients that had undergone semen analysis according to the 2010 World Health Organisation (WHO) recommendations and the Val16Ala-SOD2 SNP was genotyped by polymerase chain reaction (PCR). Oxidative parameters as well as cfDNA levels were spectrophotometrically and fluorimetrically determined. Statistical analysis included chi-square test, analysis of variance followed by Bonferroni post hoc test, as well as logistic regression multivariate analysis. Semen samples from 169 men (35.89 ± 7.33 years) were genotyped. The allelic frequencies were V= 0.485 (n = 97), A = 0.515 (n = 103), with statistically similar allelic frequencies to those of samples obtained from a general population: V = 0.509; A= 0.591. In general, AV samples presented lower numbers of sperm-altered parameters than homozygous sperm. Lipoperoxidation was higher in homozygous than heterozygous sperm samples. The results suggest that genetically caused S-HP imbalance could contribute to poor sperm quality and affect male fertility.