Influence of semen processing technique on human sperm DNA integrity.
OBJECTIVE
To compare the effects of density-gradient centrifugation and swim-up technique on sperm DNA integrity.


METHODS
Semen samples (n = 22) were obtained from consecutive nonazoospermic men presenting for infertility evaluation. Individual samples were divided into three aliquots (whole semen, density-gradient centrifugation, and swim-up) for subsequent analysis of sperm motility and DNA integrity. Sperm DNA integrity was evaluated by flow cytometry analysis of acridine orange-treated spermatozoa and expressed as the percentage of spermatozoa demonstrating denatured DNA.


RESULTS
Mean sperm motility (+/-SEM) improved significantly after processing with two-layer density-gradient and swim-up compared with whole semen (65.6% +/- 4.0% and 73.0% +/- 3.0% versus 52.0% +/- 3.6%, respectively, P <0.005), with no significant difference in motility between Percoll-treated and swim-up-treated spermatozoa. In contrast, the percentage of spermatozoa with denatured DNA was reduced significantly in swim-up-treated but not in Percoll-treated spermatozoa compared with whole semen (4.8% +/- 1. 2% and 13.6% +/- 3.6% versus 10.1% +/- 2.3%, respectively, P <0. 0001).


CONCLUSIONS
Although density-gradient centrifugation is comparable to swim-up technique in recovering spermatozoa with enhanced motility, spermatozoa recovered after swim-up possess higher DNA integrity. These data urge us to reexamine our current sperm processing techniques in order to minimize sperm DNA damage.
Zini
A
A
Division of Urology, Department of Surgery, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
Finelli
A
A
Phang
D
D
Jarvi
K
K
D002499:Centrifugation, Density Gradient / Q000009:adverse effects; D004247:DNA / Q000032:analysis* / Q000502:physiology; D004249:DNA Damage / Q000502:physiology; D005434:Flow Cytometry; D006801:Humans; D007248:Infertility, Male / Q000175:diagnosis*; D008297:Male; D009691:Nucleic Acid Denaturation / Q000502:physiology; D009845:Oligospermia / Q000175:diagnosis; D012661:Semen / Q000737:chemistry / Q000166:cytology*; D013081:Sperm Motility / Q000502:physiology; D013094:Spermatozoa / Q000737:chemistry* / Q000502:physiology
D004247:DNA