The in vitro effect of benzo[a]pyrene on human sperm hyperactivation and acrosome reaction

Objective: To evaluate the in vitro effect of benzo[a]pyrene on sperm hyperactivation and acrosome status in normozoospermic semen samples of nonsmokers analyzed by computer-assisted semen analysis (CASA). Design: Experimental in vitro study. Setting: Andrology laboratory. Patient(s): Thirteen proven fertile, normozoospermic, and nonsmoking men. Intervention(s): Spermatozoa were washed free of seminal plasma and were treated with different concentrations of benzo[a]pyrene and compared with controls treated with medium alone. The benzo[a]pyrene concentrations were: 100, 50, 25, and 12.5 μg/mL. Main Outcome Measure(s): Effect of varying concentrations of benzo[a]pyrene on sperm hyperactivation and acrosomal reaction. Result(s): A statistically significant increase in sperm hyperactivation was observed in presence of benzo[a]pyrene at concentrations of ≥50 μg/mL. The result of the acrosome halo test showed that concentrations of benzo[a]pyrene ≥25 μg/mL statistically significantly decreased the percentage of halo formation, indicating an inappropriate (false) acrosome reaction. Conclusion(s): Benzo[a]pyrene statistically significantly affected sperm functional competence as evidenced by increased hyperactivation as well as premature acrosomal reaction.