Correlation between sperm motility and sperm chromatin/DNA damage before and after cryopreservation and the effect of folic acid and nicotinic acid on post-thaw sperm quality in normozoospermic men

Abstract

Cryopreservation exposes sperm to physical and chemical stresses causing cell damages and impairs sperm functions. The aim of this study was to evaluate the association between motility and sperm chromatin/DNA damage before and after cryopreservation and investigate the effects of folic acid and nicotinic acid on post-thaw sperm quality. Thirty semen samples were obtained from 30 normozoospermic men, aged between 25 and 45 years old. Each sample were divided into five aliquots to form the following groups: fresh, cryopreserved with sperm-freeze only (control), with nicotinic acid (10 mM), with folic acid (50 nM), and with a combination of folic acid (50 nM) + nicotinic acid (10 mM). Sperm viability and motility in each group were assessed by eosin-nigrosine staining and computer-aided sperm analysis respectively. Sperm chromatin quality was studied by aniline blue, toluidine blue, acridine orange staining methods and sperm chromatin dispersion test. Cryopreservation led to a significant reduction in sperm quality in comparison to fresh sample groups (p < 0.05). Sperm chromatin damage was negatively correlated with the percentage of progressively motile cells. Supplementation of the cryopreservation medium with folic acid or nicotinic acid induced a significant improvement in sperm parameters and chromatin quality, compared to control groups (p < 0.05). Meanwhile, the combination of folic acid + nicotinic acid showed a significant protective effect in post thaw sperm. In conclusion, cryopreservation generated oxidative stress, inducingsperm cryodamage, reducing progressive motility and sperm quality, as an indicator of significant chromatin/DNA damage. Folic acid and nicotinic acid exhibited a potential cryoprotective effect by enhancing sperm quality.