Sperm cryopreservation is an efficient and cost-effective method for archiving transgenic mouse lines. Cryopreservation provides a backup in case of:
- Natural disasters like hurricanes, floods, or fires
- Pathogen outbreaks in the animal facility
- Mistakes in genotyping
- Breeding cessation due to age
- Genetic drift, which can alter reproductive performance or introduce phenotypic complexities
Cryopreservation also allows investigators to share transgenic resources more easily with other researchers for compliance with journal and funding agency sharing requirements.
Requirements
Two proven breeder males between 3-6 months of age that have been housed individually. Cryopreservation using older or unproven males can be attempted in an emergency but see the disclaimer below.
Scheduling
Contact the MGEF to schedule a date for the cryopreservation. If your mice are housed in barrier or semi-barrier rooms at the ARC, you can bring the cages to the MGEF lab in ARC 1.218 on the scheduled cryopreservation day. For mice from ARC conventional housing, we will arrange to collect tissues from the mice in the Necropsy room in ARC 1.140. For mice housed at HDB or DPRI, we will request that the Animal Resource Center transport the mice to a temporary holding room in the ARC building for tissue collection.
Service Description
The MGEF will make ten straws plus one test straw from each mouse. The test straw will be used to perform a small-scale in vitro fertilization assay to verify the cryopreservation step was successful. Typical fertilization rates are in the 50-90% range. Investigators should not remove the transgenic line from the rack until they receive the QC results from the MGEF. We consider an IVF QC rate above 25% successful. Although we have recovered a mouse line using sperm with an IVF QC rate of less than 10%, we recommend repeating the cryopreservation if the IVF rate is below 25%. The MGEF includes a positive control sperm sample to ensure the IVF assay worked adequately. We highly recommend that you store your sperm samples at the MGEF. The MGEF stores the samples in duplicate between separate liquid nitrogen storage vessels. We charge a monthly fee for storage.
Disclaimer
Age, genetic background, housing conditions, and the role of the gene mutation can influence sperm cryopreservation efficiency. The MGEF will repeat the cryopreservation at no cost If the IVF QC rate is below 25%. This guarantee applies only if we use proven breeders, they are 3-6 months of age, and they have been housed individually. The investigator will be charged for all sperm cryopreservation attempts using male mice outside these criteria.