RESUMO
OBJECTIVE: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect. G6PD plays a key role in the pentose phosphate pathway, which is a major source of nicotinamide adenine dinucleotide phosphate (NADPH). NADPH provides the reducing equivalents for oxidation-reduction reductions involved in protecting against the toxicity of reactive oxygen species such as H₂O₂. We hypothesized that G6PD deficiency may reduce the amount of NADPH in sperms, thereby inhibiting the detoxification of H₂O₂, which could potentially affect their motility and viability, resulting in an increased susceptibility to infertility. METHODS: Semen samples were obtained from four males with G6PD deficiency and eight healthy males as a control. In both groups, motile sperms were isolated from the seminal fluid and incubated with 0, 10, 20, 40, 60, 80, and 120 µM concentrations of H2O2. After 1 hour incubation at 37℃, sperms were evaluated for motility and viability. RESULTS: Incubation of sperms with 10 and 20 µM H₂O₂ led to very little decrease in motility and viability, but motility decreased notably in both groups in 40, 60, and 80 µM H₂O₂, and viability decreased in both groups in 40, 60, 80, and 120 µM H₂O₂. However, no statistically significant differences were found between the G6PD-deficient group and controls. CONCLUSION: G6PD deficiency does not increase the susceptibility of sperm to oxidative stress induced by H₂O₂, and the reducing equivalents necessary for protection against H₂O₂ are most likely produced by other pathways. Therefore, G6PD deficiency cannot be considered as major risk factor for male infertility.
