A simple comet assay for archived sperm correlates DNA fragmentation to reduced hyperactivation and penetration of zona-free hamster oocytes.
OBJECTIVE
To correlate sperm variables with sperm DNA fragmentation, as assessed by using a modified alkaline comet assay for sperm smears.


METHODS
The comet assay was adapted for fixed sperm smears (59 cases), and the level of DNA fragmentation was determined.


METHODS
Clinical and academic research environment.


METHODS
59 patients undergoing fertility treatment.


METHODS
Sperm samples leftover from IVF procedures were fixed and processed for the comet assay.


METHODS
Sperm head DNA density and sperm variables.


RESULTS
A correlation was observed between increased sperm head DNA fragmentation and decreased penetration of zona-free hamster oocytes. Heat-induced hyperactive motility decreased as DNA fragmentation increased. The DNA fragmentation did not correlate with percentages of intact acrosome, normality, maturity, and strict normal morphology.


CONCLUSIONS
The advantages of the comet assay for archived cells include simplicity, low intraassay coefficient of variation, and low performance cost; in addition, DNA analysis can be carried out at leisure. Low DNA damage was associated with higher hyperactivation and oocyte penetration, suggesting that failed fertilization was linked to compromised DNA integrity in the sperm. Exploration of compounds to repair damaged DNA is warranted.
Chan
P J
PJ
Department of Gynecology, Center for Fertility and In Vitro Fertilization, Loma Linda University School of Medicine, Loma Linda, California 92354, USA.
Corselli
J U
JU
Patton
W C
WC
Jacobson
J D
JD
Chan
S R
SR
King
A
A
D000165:Acridine Orange; D000177:Acrosome / Q000502:physiology / Q000648:ultrastructure; D000818:Animals; D006224:Cricetinae; D053938:DNA Fragmentation / Q000502:physiology*; D005260:Female; D005456:Fluorescent Dyes; D006358:Hot Temperature; D006801:Humans; D008297:Male; D009691:Nucleic Acid Denaturation; D009865:Oocytes / Q000502:physiology*; D012661:Semen / Q000166:cytology; D013081:Sperm Motility / Q000502:physiology; D013084:Sperm-Ovum Interactions / Q000502:physiology*; D013094:Spermatozoa / Q000378:metabolism / Q000502:physiology*; D015044:Zona Pellucida / Q000473:pathology*
D005456:Fluorescent Dyes; D000165:Acridine Orange