[The effect of the period of cryopreservative storage on the cryosurvival of human spermatozoa].
OBJECTIVE
To study the effect of cryopreservative period on the cryosurvival of human spermatozoa and find out the optimal recovery time of cryopreservation.


METHODS
Eighty-eight semen samples were collected from normal donors and divided randomly into 5 groups according to the period of cryopreservative storage (1 d, 7 d, 30 d, 180 d, 300 d) in liquid nitrogen after being frozen by the programized, three-step freezing method. Fresh and frozen-thawed semen were examined by the routine analysis of semen and then the sperm recovery rate were calculated.


RESULTS
There were no significant differences in sperm recovery rate between group I and the others (P > 0.05). The period of cryopreservative storage in liquid nitrogen had no correlation with the cryosurvival of human spermatozoa (r = 0.05, P > 0.05).


CONCLUSIONS
It was indicated that freezing-thawing after 24 h would be helpful to the screening of semen donors in batches for donor insemination of human sperm bank.
Human Sperm Bank, Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China.
Jin-Xia
JX
Ma
Li-Xin
LX
Qian
Tian-Hua
TH
Jiang
Qiang
Q
Lu
Hong-Fei
HF
Wu
D015925:Cryopreservation; D006801:Humans; D008297:Male; D012662:Semen Preservation; D013074:Sperm Banks; D013094:Spermatozoa / Q000502:physiology*; D013997:Time Factors