Effects of ulipristal acetate on sperm DNA fragmentation during in vitro incubation.

Objective: Ulipristal acetate (UPA) acts as an emergency contraceptive by inhibiting ovulation. This study explores possible additional effects on the fragmentation of sperm DNA during in vitro incubation.

Methods: Motile spermatozoa from healthy donors were selected by swim-up and incubated under capacitating conditions in control medium or with UPA (1, 10, 100, 1,000 or 10,000 ng/ml). In some experiments, 200 μM of H2O2 were added to induce oxidative stress. The sperm chromatin dispersion test was performed to analyse DNA integrity (400 cells; 1000×). Lipid peroxidation (thiobarbituric acid assay), induced-acrosome reaction (AR) and sperm vitality (Eosin Y) were also evaluated in spermatozoa exposed to UPA and/or H2O2.

Results: During sperm incubation, the percentage of fragmented DNA increased significantly, from 15.0 ± 1.3 to 41.0 ± 4.5% (p < 0.001). In the presence of UPA, DNA fragmentation decreased significantly (p < 0.05), in a dose-dependent manner. At 100 and 1000 ng/ml, UPA also counteracted the effect of H2O2 and prevented DNA fragmentation. No effect on sperm vitality, lipid peroxidation or induced-AR was found with any treatment.

Conclusions: During in vitro sperm capacitation DNA fragmentation increased but the latter was counteracted in the presence of UPA, which possibly acted as a scavenger of reactive oxygen species produced by spermatozoa.