Comparison between mechanical freezer and conventional freezing using liquid nitrogen in normozoospermia.
BACKGROUND
This study evaluated the effect of human semen cryopreservation using an ultra-low temperature technique with a mechanical freezer at -85°C as an alternative method to the conventional liquid nitrogen technique at -196°C.


METHODS
This was a prospective experimental study conducted in the Medically Assisted Conception unit, Department of Obstetrics and Gynaecology, National University Hospital, Malaysia from January 1, 2006 to April 30, 2007. All normozoospermic semen samples were included in the study. The concentration, motility and percentage of intact DNA of each semen sample were assessed before and after freezing and thawing on Days 7 and 30 post freezing.


RESULTS
Sperm cryopreservation at -85°C was comparable to the conventional liquid nitrogen technique for a period of up to 30 days in a normozoospermic sample. There was no statistical difference in concentration (Day 7 p-value is 0.1, Day 30 p-value is 0.2), motility (Day 7 p-value is 0.9, Day 30 p-value is 0.5) and proportion of intact DNA (Day 7 p-value is 0.1, Day 30 p-value is 0.2) between the ultra-low temperature technique and conventional liquid nitrogen cryopreservation at Days 7 and 30 post thawing.


CONCLUSIONS
This study clearly demonstrates that short-term storage of sperm at -85°C could be a viable alternative to conventional liquid nitrogen cryopreservation at -196°C due to their comparable post-thaw results.
Department of Obstetrics and Gynaecology, National University of Malaysia, Jalan Yaacob Latiff, Bandar Tun Razak, Kuala Lumpur 56000, Malaysia. drrahana@ppukm.ukm.my
A R
AR
Rahana
S P
SP
Ng
C F
CF
Leong
M D
MD
Rahimah
D000328:Adult; D015331:Cohort Studies; D015925:Cryopreservation / Q000379:methods*; D005615:Freezing; D006801:Humans; D008296:Malaysia; D008297:Male; D008875:Middle Aged; D009584:Nitrogen / Q000737:chemistry*; D011446:Prospective Studies; D012662:Semen Preservation / Q000379:methods*; D012680:Sensitivity and Specificity; D013048:Specimen Handling; D013076:Sperm Count; D013081:Sperm Motility; D013997:Time Factors
D009584:Nitrogen