Objective: To examine and compare the effects of density-gradient centrifugation on the integrity of sperm DNA from the semen of both fertile and infertile men.
Design: Prospective, observational study.
Setting: University infertility clinic.
Patients: Forty-four nonazoospermic, infertile men and nine fertile controls.
Interventions: Semen samples were processed by density-gradient centrifugation. Sperm motility and sperm chromatin structure (evaluated by flow cytometry analysis of acridine orange-treated spermatozoa) were monitored before and after semen was processed.
Main Outcome Measures: Sperm motility and DNA integrity.
Results: Following density-gradient centrifugation, mean sperm motility (±SEM) improved significantly compared to whole semen in samples from fertile and infertile men, respectively (71 ± 6 vs. 49 ± 7% and 56 ± 3 vs. 44 ± 3%, P<0.05). However, the percentage of sperm with denatured DNA increased compared to whole semen after processing of samples from infertile (25 ± 3 vs. 15 ± 2%, P<0.01) but not fertile men (9 ± 3 vs. 8 ± 2%, P>0.05).
Conclusions: Our data indicate that the potential detrimental effect of density-gradient centrifugation on sperm DNA integrity is related to the initial semen quality. These data urge us to examine our current sperm-processing techniques to minimize sperm DNA damage.
