Cryopreservation of Sperm ($312.18 per strain):
- 2-3 male mice which are between the ages of 10-16 weeks are needed to perform this service. We will freeze down 21 straws worth of sperm, and will store them in liquid nitrogen. A post-thaw viability check and an in vitro fertilization (IVF) to the 2-cell stage will be performed on one of the straws.
- Sperm cryopreservation presents the opportunity to substantially reduce the number of mice used to both store and re-establish a mouse line. Sperm collected from a single male can potentially give rise to large numbers of offspring following IVF of oocytes. The efficiencies of sperm cryopreservation are strain-dependent.
- The disadvantage of sperm cryopreservation is that monoploid genome is preserved. The sperm cryopreservation service does not guarantee recovery to live born by IVF, and for some strains ICSI is required for recovery. Sperm counts, motility and morphology will be analyzed before cryopreservation.
Cryopreservation of Mouse Embryos:
- Our professional staff will determine the quantity of embryos to cryopreserve, and the most efficient procedure for embryo collections. In vitro quality control to indicate the success of cryopreservation is performed on every batch of embryos.
- Embryo collections can be done one of two ways:
- Traditional mating, collection and freezing ($515 per session) PLUS the cost of females: Traditional mating, collection and freezing: Specifically, stud males are mated weekly with egg donors per cryopreservation session to produce embryos for cryopreservation. On average, it takes 2-4 embryo collection sessions to freeze down enough embryos to guarantee recovery in this traditional way. If using homozygous males then fewer sessions will be needed. However, it may take more sessions if the mouse strain has a low superovulation rate, the stud males have low fertility, or males are too old. Some strains cannot be successfully cryopreserved. The investigator is responsible for providing all stud males, embryo donors, and per diem costs for these animals. Females will be superovulated by the TG facility and mated with males, and embryos will be harvested and cryopreserved. This procedure will be repeated until a sufficient number of embryos are cryopreserved. Embryos are isolated and cryopreserved in straws and stored in liquid N2.
- IVF, collection and freezing ($1326 per session) PLUS the cost of females:
- Females will be superovulated by the TG facility and embryos will be created through IVF with frozen or fresh sperm. Embryos will be cryopreserved at the 2-cell stage. This procedure will be repeated until a sufficient number of embryos are cryopreserved. This usually should only take one session, but sometimes a second is needed.
- Embryos are cryopreserved in straws and stored in liquid N2.
The Gene Targeting and Transgenic Shared Resource stores embryos in two separate tanks at Roswell Park Comprehensive Cancer Center in Buffalo, NY. (Storage is $10/strain/year)