Embryo Cryopreservation

Cryopreservation of embryos is a useful technique for preserving transgenic mouse lines for future experiments. The process involves superovulating wildtype female mice and mating them with male stud mice provided by the investigator. Embryos are recovered and cryopreserved at the 2-cell to blastocyst stage in straws, with the goal of preserving a minimum of 250 heterozygous or 150 homozygous embryos.

Cryopreservation of embryos is recommended for homozygous lines or lines with multiple genetic mutations. This technique is more suitable for preserving the genetic material of such lines, as it provides a greater chance of preserving the genetic mutations in the embryos.

Embryos can also be cryopreserved after performing in vitro fertilization, using fresh or frozen sperm cultured with wildtype eggs donated from superovulated females. The resulting fertilized embryos can be transferred to produce live pups or cryopreserved at the two-cell stage.

Frozen embryos are stored in liquid nitrogen storage tanks and are monitored weekly by personnel of the resource. A yearly storage fee applies to each line, unless the lines are donated to the Vanderbilt Cryopreserved Mouse Repository.

Timeline:

1. PI submits a service request iLab Organizer (corefacilities.org)
2. Service requests are reviewed and approved by the Director and Manager of the facility
3. Experiments are scheduled
4. Cryopreservation is performed and straws are placed into long term storage
5. One to two straws of embryos will be thawed to check embryo viability
6. PI notified about results of viability check