Long-term liquid nitrogen vapor storage of mouse embryos cryopreserved using vitrification or slow cooling.
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).
Eum
Jin Hee
JH
Fertility Center of CHA General Hospital, CHA Research Institute, Pochon CHA University College of Medicine, Seoul, South Korea.
Park
Jae Kyun
JK
Lee
Woo Sik
WS
Cha
Kwang Ryul
KR
Yoon
Tae Ki
TK
Lee
Dong Ryul
DR
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
D009584:Nitrogen