title: Effect of liquid nitrogen vapor storage on the motility, viability, morphology, deoxyribonucleic acid integrity, and mitochondrial potential of frozen-thawed human spermatozoa.
abstract: OBJECTIVE
  To evaluate the effectiveness of liquid nitrogen (LN(2)) vapor (indirect contact method) for the storage of human semen.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  University hospital-based fertility center.
  
  
  METHODS
  We evaluated 150 patients with normal sperm parameters.
  
  
  METHODS
  Human semen (N = 120) was mixed with Semen Freezing Medium, divided into two groups, frozen, and stored in LN(2) or LN(2) vapor. Frozen semen from each group (n = 40) was thawed after storage for 1 week, 1 month, or 3 months and then analyzed. In the second experiment, semen (n = 30) was divided into four groups, frozen, and stored in LN(2) or stored 7 cm, 12 cm, or 17 cm above the surface of LN(2) for 1 week.
  
  
  METHODS
  The motility and viability of sperm were evaluated by basic analysis, the morphology was analyzed with use of staining, the DNA integrity was assessed with use of terminal deoxyuridine triphosphate nick end-labeling assays, and active mitochondria were detected with use of rhodamine 123 staining.
  
  
  RESULTS
  The LN(2) and LN(2) vapor groups did not differ with regard to sperm motility, viability, morphology, DNA integrity, or active mitochondria when the cryostorage periods were compared. Furthermore, the quality of sperm stored within 17 cm of the surface of LN(2) for 1 week did not change.
  
  
  CONCLUSIONS
  The storage of human semen in LN(2) vapor, without direct contact with LN(2), may represent a useful alternative for the effective storage of human semen.
authors.affiliation: Fertility Center of CHA Gangnam Medical Center, College of Medicine, CHA University, Seoul, South Korea.
authors.forename: Jung Jin
authors.initials: JJ
authors.lastname: Lim
authors.forename: Tai Eun
authors.initials: TE
authors.lastname: Shin
authors.forename: Seung-Hun
authors.initials: SH
authors.lastname: Song
authors.forename: Chong Won
authors.initials: CW
authors.lastname: Bak
authors.forename: Tae Ki
authors.initials: TK
authors.lastname: Yoon
authors.forename: Dong Ryul
authors.initials: DR
authors.lastname: Lee
mesh_terms: D000328:Adult; D048430:Cell Shape / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation / Q000379:methods; D053938:DNA Fragmentation / Q000187:drug effects*; D005615:Freezing / Q000009:adverse effects; D005740:Gases / Q000009:adverse effects / Q000494:pharmacology; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D009584:Nitrogen / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology*; D044367:Phase Transition; D055101:Semen Analysis; D012662:Semen Preservation / Q000009:adverse effects / Q000379:methods; D013081:Sperm Motility / Q000187:drug effects*; D013094:Spermatozoa / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D005740:Gases; D009584:Nitrogen