Cryodamage on Sperm Chromatin According to Different Freezing Methods, Assessed by AO Test
Somsin Petyim MD*, Roungsin Choavaratana MD*
Affiliation : * Infertility Unit, Department of Obstetrics and Gynecology, Faculty of Medicine, Siriraj Hospital
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).
Materials and 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 signifi-
cantly provided superior post-thaw sperm motility, vitality and cryosurvival rate, compared with the liquid
nitrogen vapour freezing method.
Conclusion : Computerized program freezing is recommended as a first choice method for routine cryostorage.
Keywords : Liquid nitrogen vapour, Computerized program freezer, Cryopreservation, Sperm DNA integrity
