3-nitrotyrosine and Infertility--Male

Nitric oxide (NO) is a signaling molecule responsible for initiation of molecular events that influence sperm functionality in a concentration-dependent manner. It is still not fully understood how seminal plasma NO contributes to sperm pathologies. The aim of this study was to elucidate whether and how NO is implicated in etiology of different sperm abnormalities. To this end we determine NO, nitrite and 3-nitrotyrosine (3-NT) content in seminal plasma of infertile men with specific pathologies (terato-, oligoterato- and oligoasthenoteratospermia) and relate it to infertile normospermic samples. To gain further understanding of NO metabolism in seminal plasma we determine protein expression of endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS). Here we show that NO, nitrite and 3-NT levels in seminal plasma of men with suboptimal semen parameters are significantly lower compared to normospermic men. An increase in protein expression of eNOS and no change in protein expression of iNOS is observed in men with sperm pathologies. Association of seminal plasma 3-NT level with functional sperm parameters is observed - positive correlation with sperm count, motility and morphology in normospermia, teratospermia and oligoteratospermia, as well as negative correlation with sperm morphology and motility in oligoasthenoteratospermia. Present study revealed that suboptimal seminal plasma NO content is found in all examined sperm pathologies. This result unequivocally shows the importance of NO for sperm function and involvement of suboptimal NO level in etiology of sperm abnormalities. Lower seminal plasma 3-NT level and its significant association with sperm parameters, found in pathologies, strongly indicates that protein nitration is important for spermatozoa function and that failure to establish this post-translational protein modification might be involved in etiology of sperm abnormalities. According to our results, NO measurement can discriminate infertile men with sperm pathologies from infertile normospermic men but is not indicative of a specific type of sperm pathology.

Topics: Adult; Antioxidants; Humans; Infertility, Male; Male; Nitric Oxide; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Nitrites; Semen; Sperm Count; Sperm Motility; Tyrosine

To detect peroxynitrite and 3-nitrotyrosine production in human spermatozoa of asthenozoospermic infertile patients and normospermic donors, and evaluate any influence on kinetic sperm features.. Basic study.. Andrology Unit, Dept of Internal Medicine and Biochemistry Institute, Polytechnic University of Marche, Italy.. Sixty-nine infertile patients affected by idiopathic asthenozoospermia and 29 normal fertile donors.. No therapeutic intervention was performed on patients.. Production of peroxynitrite (ONOO-) and 3-nitrotyrosine by human spermatozoa; kinetic sperm cells parameters.. Normospermic fertile donors exhibited ONOO- concentrations significantly lower than those of asthenozoospermic infertile men (9.11 +/- 3.37 vs. 27.46 +/- 5.77 nmol/10(6) cells); confocal microscopy showed that ONOO- was more evident in spermatozoa of patients than in healthy donors. Moreover, a significant negative correlation was evident between ONOO- concentration and total sperm motility, curvilinear velocity (VCL), straight progressive velocity (VSL), and linearity coefficient. Finally, an increase was found in the nitration of the tyrosine residues in asthenozoospermic samples compared to controls.. Spontaneous tyrosine nitration occurs in human spermatozoa. This post-translational protein modification is enhanced by an overproduction of peroxynitrite, which is more evident in asthenozoospermic infertile patients when compared with normospermic fertile donors. Motility parameters are negatively affected, suggesting that ONOO- may be involved in defective sperm function.

Topics: Adult; Humans; Infertility, Male; Male; Peroxynitrous Acid; Sperm Motility; Spermatozoa; Tyrosine