Embryo cryopreservation involves the generation of pre-implantation embryos using males provided by the investigator and the controlled rate cooling of collected embryos to -30°C followed by rapid freezing of embryos in liquid nitrogen to -196°C.
While embryo cryopreservation is the gold standard for preserving mouse germplasm, not all mouse strains are suitable for embryo cryopreservation. However, we have been successful at cryopreserving embryos from several different mouse strains.
Embryos for cryopreservation can be obtained in two basic ways:
- via in vitro fertilization (IVF) using freshly isolated sperm and oocytes collected from hormonally-treated females, a method referred to as speed cryogenics
- via natural mating of hormonally-treated females fertile males (requires technical assistance from your lab)
Speed cryogenics is the most common method used for embryo cryopreservation projects as hundreds of embryos can be generated by IVF in a single day.
To cryopreserve homozygous embryos, it is essential to used both homozygous females and homozygous males to generate the embryos.