Embryo Cryopreservation
For safe cryopreservation of embryos, we freeze 300 embryos from homozygous males and 400 embryos from heterozygous males mated with wild type females. We would ask you to provide between 5-10 2-6 months old males. We will mate them with super-ovulated wild type females for which you can choose different background strains. Please inform us about any fertility issues your line might have. With this method, you conserve embryos with your complete strain-background crossed once more with the desired wild type-background.
Sperm Cryopreservation
For fast cryopreservation you can also choose to freeze sperm instead of embryos. For this, we would need at least 2 male mice between 2-6 months old, ideally proven breeders. We will freeze sperm pooled from both males in about 20 straws and test one straw for performance by in vitro fertilization (IVF) after thawing. With this method you conserve the male half of your strain-background. If desired, we can combine the IVF with an embryo transfer to directly re-derive the mouse in our SPF-facility.
Rederivation and Embryo Transfer
For rederivation of frozen embryos or establishment of imported mouse lines into our clean SPF area, we offer embryo transfer. We will mate your male mice with super-ovulated (wild type) females and transfer the resulting or revitalized embryos into foster mice. A minimum of 5 males or at least 50 frozen embryos would be required for this process. The import of living mice is only possible if the health status of these mice complies with our standards for the quarantine lab (for more information please send the current health certificate for your mice). If the health status does not allow import into our quarantine, import as frozen embryos, or sperm (via IVF) is possible. After the transfer, serum from the foster mothers will be tested to make sure the mice are free of all relevant viruses (according to FELASA recommendation). A transfer is completed as soon as the first transgenic animal is genotyped in the clean SPF area.
in vitro Fertilization
To recover a mouse line from frozen sperm, we offer in vitro fertilization using donor eggs from super-ovulated wild type female mice for which you can select different mouse strains. After IVF the resulting 2-cell stage embryos are transferred into pseudo-pregnant foster mothers. After the transfer, serum from the foster mothers will be tested to make sure the mice are free of all relevant viruses (according to FELASA recommendation). A project is completed as soon as the first transgenic animal is genotyped in the clean SPF area.