Cryodamage on sperm chromatin according to different freezing methods, assessed by AO test.

ABSTRACT

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). MATERIAL AND METHOD: 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. CONCLUSION: Computerized program freezing is recommended as a first choice method for routine cryostorage.