Authors

Jingmei Hu, M.D., Shidou Zhao, Ph.D., Chengyan Xu, Ph.D., Lin Zhang, M.D., Shaoming Lu, Ph.D., Linlin Cui, Ph.D., Jinlong Ma, Ph.D., Zi-Jiang Chen, Ph.D.

Volume 104, Issue 5, Pages 1253-1257

Abstract

Objective:

To compare the differences in the characteristics of post-thaw human sperm after storage in either liquid nitrogen (LN2; −196°C) or LN2 vapor (−167°C).

Design:

Experimental study.

Setting:

University hospital.

Patient(s):

Thirty healthy volunteers who agreed to donate their normal semen samples for infertility or research were included in the study.

Intervention(s):

Semen samples (n = 30) were divided into eight aliquots and frozen. Four aliquots of each human semen sample were stored in LN2 (−196°C), and the other four aliquots were stored in LN2 vapor (−167°C). After 1, 3, 6, or 12 months, samples were thawed and analyzed.

Main Outcome Measure(s):

The motility was evaluated by the manual counting method. The viability was estimated by eosin staining. The morphology was analyzed by Diff-Quik staining. The sperm DNA integrity was determined with acridine orange fluorescent staining, and acrosin activity was assayed by the modified Kennedy method.

Result(s):

The characteristics of post-thaw human sperm, including motility, viability, morphology, DNA integrity, and acrosin activity, showed no significant difference between LN2 and LN2 vapor storage for the different time periods.

Conclusion(s):

LN2 vapor was comparable to LN2 in post-thaw sperm characteristics, suggesting that LN2 vapor may be substituted for LN2 for the long-term storage of human sperm.

Read the full text at: http://www.fertstert.org/article/S0015-0282(15)01651-9/fulltext