A complete list of rules for naming mouse strains and alleles is available on the Mouse Genome Informatics website.
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Information on mouse strain nomenclature is available at the Jax website. In particular, we need to know the precise formal strain name before we can schedule the cryopreservation. In addition to the Service Request Form, we must also receive a completed copy of our Strain Data Sheet for each strain. To order services involving embryo or sperm cryopreservation or thawing, please request a Service Request Form from Jon Neumann. Signed forms should be delivered to Jon Neumann via e-mail. Thus, in some cases, embryo cryopreservation may still be necessary.
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Mouse strains that are difficult to replace should be cryopreserved to allow reconstitution in the event of a pathogen outbreak, natural disaster, or other occurrence that may result in the loss of all existing breeding stock.īack to Top Comparison of Embryo and Sperm CryopreservationĪ complete cycle of cryopreserving a strain and reconstituting it from frozen material involves the same biological steps whether one uses embryos or sperm.When mouse strains are not immediately needed for experimental purposes, but may be needed at a later date and cannot be readily obtained from vendors, it may be more economical to store the strain as frozen embryos or sperm, rather than maintaining a live colony.The cryopreservation of mouse strains serves two main functions:
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Improvements from Kumamoto University (Takeo and Nakagata, Biology of Reproduct(2011)) have been shown to make sperm cryopreservation as reliable as embryo cryopreservation (although the latter may still be necessary for some strains). Sperm from popular strains such as C57BL/6J produced very low yields of fertilized embryos after thawing and performing in vitro fertilization (IVF). Historically, the revival of mice from cryopreserved sperm has suffered from large strain-to-strain variations in efficiency. Sperm cryopreservation involves harvesting the cauda epididymis from euthanized males, releasing the sperm into a cryoprotective solution, loading the sperm suspension into semen straws, incubating the straws in the vapor phase of liquid nitrogen, plunging them into the liquid phase, and storing them in liquid nitrogen. The most robust method of embryo cryopreservation uses 8-cell stage embryos that are infused with a cryoprotectant, slowly lowered to –35C, and then rapidly submerged in, and stored in, liquid nitrogen (-196C). Using appropriate thawing techniques, germplasm or pre-implantation embryos stored in this manner can be used to regenerate live mice.Įmbryos can be cryopreserved at all stages of pre-implantation development. Sperm or pre-implantation stage embryos can be isolated from mice and treated with a cryoprotective agent that allows the germplasm or pre-implantation embryos to be stored indefinitely at ultra-low temperature (i.e. Comparison of Embryo and Sperm Cryopreservation.Embryo & Sperm Cryopreservation and Revival Services