Nuclear maturity of human spermatozoa selected by swim-up or by Percoll gradient centrifugation procedures

Objective: To investigate the relationship between sperm preparation techniques and nuclear maturity, as evidenced by the electrophoretic profiles of sperm nuclear proteins. Design: Analysis of sperm nuclear quality in sperm populations used for NF. Setting: Center for infertility and assisted reproductive technology and university departments. Patients: Twenty-seven men undergoing an infertility work-up. Main Outcome Measures: Comparative electrophoretic investigation of nucleoproteins extracted from spermatozoa selected by swim-up or Percoll techniques. Results: Nuclear maturity level is improved after the two methods of selection but is more improved after Percoll. In the two groups, selected spermatozoa contain less histones. Moreover, Percoll gradients appeared to enrich for spermatozoa with less intermediate proteins and more mature nucleoproteins of P2 family than swim-up spermatozoa. Conclusion: Percoll may offer advantages in terms of the quality of the selected spermatozoa that may influence the outcome of assisted conception techniques.