Low human sperm motility coexists with sperm nuclear DNA damage and oxidative stress in semen

Background: Low sperm motility, one of the common causes of male infertility, is associated with abnormal sperm quality. Currently, important sperm/semen biomarkers are sperm chromatin status and oxidation-reduction potential (ORP) in semen. Because the association between sperm motility and these biomarkers is still not fully clarified, our study was designed to verify the distribution and risk of sperm DNA fragmentation (SDF) and oxidative stress in semen in asthenozoospermic men.Materials and methods: This study was carried out on discharged sperm cells of asthenozoospermic men (isolated asthenozoospermia or coexisted with reduced sperm number and/or morphology), nonasthenozoospermic men (reduced total sperm count and/or sperm morphology) (experimental groups) and normozoospermic men (proven and presumed fertility) (control group). Basic semen analysis was evaluated according to the 6th edition of the World Health Organization manual guidelines. SDF was assessed using the sperm chromatin dispersion test, while static(s) ORP in semen was measured by means of a MiOXSYS analyser.Results: The men from the asthenozoospermic group had lower basic semen parameters than those from the control and nonasthenozoospermic groups. In men with poor sperm motility SDF and sORP, prevalence and risk for > 20% SDF (high level of DNA damage) and for > 1.37 sORP (oxidative stress) were significantly higher than those of control and nonasthenozoospermic subjects. The risk for sperm DNA damage and oxidative stress in asthenozoospermic men was over 10-fold higher and almost 6-fold higher than those in control subjects and almost or over 3-fold higher than those in nonasthenozoospermic men.Conclusions and discussion: Poor human sperm motility coexisted with low basic sperm quality. Sperm DNA damage and oxidative stress in semen were much more frequent in asthenozoospermia. These abnormalities can decrease the sperm fertilizing capability under both natural and medically assisted reproduction conditions. Thus, in asthenozoospermia, the evaluation of sperm chromatin status and oxidation-reduction potential in semen is justified and inevitable, and the appropriate antioxidant therapy can be suggested.