title: Long-term liquid nitrogen vapor storage of mouse embryos cryopreserved using vitrification or slow cooling.
abstract: OBJECTIVE
  To store embryos in LN(2) vapor, which eliminates direct contact with LN(2), is presented as an alternative method to protect embryos cryopreserved by vitrification or slow cooling from LN(2)-borne pathogens.
  
  
  METHODS
  Basic animal research.
  
  
  METHODS
  University-affiliated hospital.
  
  
  METHODS
  Two-cell mouse embryos collected from superovulated ICR mice.
  
  
  METHODS
  Embryos cryopreserved by vitrification or slow cooling were stored in LN(2) or LN(2) vapor and then thawed after 1 week, 1 month, or 6 months. Thawed embryos cultured to the blastocyst stage in vitro were evaluated or transferred into the uterus of foster mothers.
  
  
  METHODS
  Survival, apoptosis, and in vitro and in vivo development of freeze-thawed mouse embryos as a function of cryopreservation and cryostorage methods were determined.
  
  
  RESULTS
  After short- and long-term storage of vitrified and slow-cooled embryos, embryonic survival and development rate were the same for embryos stored in LN(2) vapor and in direct contact with LN(2). Cell numbers and apoptosis frequency were similarly indistinguishable between the two groups after storage of embryos for 6 months, and there were no differences in delivery rate or litter size after ET.
  
  
  CONCLUSIONS
  The present study shows that embryos stored in LN(2) vapor retain full developmental potential. This storage system thus represents a useful alternative for safe and effective long-term storage of embryos that avoids direct contact with LN(2).
authors.affiliation: Fertility Center of CHA General Hospital, CHA Research Institute, Pochon CHA University College of Medicine, Seoul, South Korea.
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Eum
authors.forename: Jae Kyun
authors.initials: JK
authors.lastname: Park
authors.forename: Woo Sik
authors.initials: WS
authors.lastname: Lee
authors.forename: Kwang Ryul
authors.initials: KR
authors.lastname: Cha
authors.forename: Tae Ki
authors.initials: TK
authors.lastname: Yoon
authors.forename: Dong Ryul
authors.initials: DR
authors.lastname: Lee
mesh_terms: D000818:Animals; D017209:Apoptosis; D015925:Cryopreservation / Q000379:methods*; D046149:Embryo Culture Techniques; D047108:Embryonic Development; D005260:Female; D051379:Mice; D008813:Mice, Inbred ICR; D009584:Nitrogen; D014835:Volatilization
chemical_list: D009584:Nitrogen