CAT-262CT Genotype shows higher catalase activity in seminal plasma and lower risk of male infertility

Catalase (CAT), the key enzyme for high H2O2 elimination, constitutes, along with superoxide dismutase (SOD) and gluthatione peroxidase (GPX), the main enzymatic antioxidant system. Catalase enzyme plays an important role in seminal antioxidant defence and is present in seminal plasma at high concentrations. Low concentrations of catalase enzyme in seminal plasma have been related with male infertility. The objective of this study was to evaluate the correlation between the CAT C-262T polymorphism and male infertility. Semen samples from 400 infertile patients and 80 donors with proven fertility were included in the study. Standart semen parameters, DNA integrity and oxidative stress were evaluated. Genotype frequencies for the CAT C-262T polymorphism were determined by PCR-RFLP. Catalase concentration and activity in seminal plasma were evaluated by western-blot and activity gels respectively while catalase mRNA levels in mature spermatozoa were evaluated by qPCR. The CC genotype was associated with an increased risk of male infertility (OR = 1.976; CI = 1.241-3.216; P = 0.006) while the CT genotype was associated with a protective effect against infertility (OR = 0.479; CI = 0.293-0.783; P = 0.003). Functionally, the CT genotype showed higher concentrations of the enzyme in seminal plasma as well as 2.70 times higher activity levels than the CC genotype. Also, the CT genotype showed 3.5 higher levels of CAT mRNA in the mature spermatozoa than the CC genotype. This suggests that the CAT-262CT genotype correlates with a lower risk of suffering male infertility.