In vitro effect of vitamin D on sperm motility and oxidative stress in spermatozoa from infertile men

Abstract Calcium influx plays a role in optimizing sperm motility and capacitation that correlates with favorable pregnancy outcomes in both natural and assisted reproductive technologies. Vitamin D was found to promote calcium homeostasis in the male reproductive system by genomic and nongenomic pathways. Our study aimed to estimate in vitro effects of vitamin D on sperm motility and antioxidant capacity by adding vitamin D in purified spermatozoa. Forty-one samples with normal sperm motility according to the World Health Organization 2010 criteria were recruited. Density gradient centrifugation was used to isolate sperm in two fractions, pellet and ring layers, divided to measure effects of vitamin D on sperm motility and kinematics compared with untreated samples using computer-assisted semen analysis. Afterwards, samples underwent the intracellular reactive oxygen species test measured by Dichlorofluorescein diacetate (DCFH-DA). No significant changes were observed in the pellet layer but the ring layer revealed improved sperm motility (+ 4.2% versus − 5.4%) and kinematic parameters. However, DCFH-DA measurement showed no significant difference in both groups. In this study, increasing sperm motility and kinematic parameters were shown in ring layer sperm after adding vitamin D.