Cryodamage on sperm chromatin according to different freezing methods, assessed by AO test.
OBJECTIVE
To evaluate cryodamage effects on human sperm chromatin, motility and cryosurvival rate after freeze-thawing, compared between liquid nitrogen vapour and computerized program freezer, assessed by acridine orange staining method (AO test).


METHODS
Fifty semen samples were used. After semen analysis, each semen sample was mixed with cryoprotective media and divided into 2 straws. The first straw was frozen with liquid nitrogen vapour and the second with computerized program freezer. After 1 month of cryostorage, semen samples were thawed. Sperm chromatin integrity, motility, morphology, vitality and sperm cryosurvival rate were determined.


RESULTS
DNA damage was significantly greater (p < 0.001) following freezing with liquid nitrogen vapour than with computerized program freezer. Furthermore, the computerized program freezing method significantly provided superior post-thaw sperm motility, vitality and cryosurvival rate, compared with the liquid nitrogen vapour freezing method.


CONCLUSIONS
Computerized program freezing is recommended as a first choice method for routine cryostorage.
Petyim
S
S
Infertility Unit, Department of Obstetrics and Gynecology, Faculty of Medicine, Siriraj Hospital, Bangkok, Thailand. somsin101@yahoo.com
Choavaratana
R
R
D000165:Acridine Orange; D000328:Adult; D002470:Cell Survival; D002843:Chromatin / Q000648:ultrastructure; D003201:Computers; D015925:Cryopreservation; D004249:DNA Damage; D006801:Humans; D008297:Male; D009584:Nitrogen; D012662:Semen Preservation / Q000379:methods*; D013081:Sperm Motility; D013094:Spermatozoa / Q000502:physiology* / Q000648:ultrastructure
D002843:Chromatin; D000165:Acridine Orange; D009584:Nitrogen