Effect of sperm glutathione peroxidases 1 and 4 on embryo asymmetry and blastocyst quality in oocyte donation cycles

Objective: To prospectively determine the impact of concrete components of the sperm oxidative glutathione, stress system in terms of an enzymatic activity and mitochondrial RNA (mRNA) expression on embryo quality and reproductive outcome. Human spermatozoa use the gluthione system to inactivate reactive oxygen metabolites, and there is a close correlation between some components of the gluthianone system and male fertility. However, very few data are published regarding this system in sperm cells and its effect on fertilization ability and embryo development in human beings. Design: An oocyte-donation model used to homogenize the female factor. Setting: University-affiliated private IVF setting. Patient(s): Semen samples form infertile males (n = 43) of couples undergoing oocyte-donation cycles (n = 43). Intervention(s): None. Main Outcome Measure(s): Gene expression and activity of gluthione peroxidases (GPXs) 1 and 4, gluthione reductase, and intracellular gluthione (GSH) by fluorescent quantitative polymerase chain reaction and spectrophotometry respectively. Result(s) Fertilization rate, pronuclear number, asymmetry, and pronuclear body distribution were not correlated with any sperm gluthione parameters that were considered. When day 3 embryo parameters were evaluated, only GPX4mRNA expression in sperm cells was statistically significantly lower when asymmetric embryos were observed. Also, worst embryo development and morphology on day 5 was statistically significantly correlated with lower sperm GPX1 activity (101.07 vs. 259.8 IU/mg protein). Gluthione system analysis in fresh sperm was not statistically significantly different in patients achieving pregnancy compared with those who not, and we did not find any correlation with implantation rate. Conclusion(s): We have been able to correlate embryo morphology on day 3 with the sperm expression of GPX family members. The results indicate that sperm-derived mRNA may condition human embryo quality and persist even to blastocyst stage. The correlation of the sperm GPX family mRNA expression with embryo health appears quite promising for discovery of molecular causes of male infertility.