Sperm cryopreservation is an efficient, reliable, and cost-effective means of safeguarding and maintaining stocks of critical GEM resources. Investigators prepare 1-3 males between the age of 3 –7 months for each mouse line to be preserved. Sperm is cryopreserved in straws and subsequently test via in vitro fertilization for motility and fertilization capacity.
What will happen
- The investigator will submit a request form through iLab, filling out detail information on the number of males, ages, and any known reproductive defects. An account number must be provided at this time.
- The core will review the investigator-provided information and approve the request. The core will schedule the cryopreservation and confirm it with the investigator.
- The investigator will either deliver the mice to the biosafety hood in to ABBR R119A or have the mice transferred to the core by the CCM transfer system. The investigator needs to write the iLab request number on the cage card and leave the PI’s census card on the cage. If the mice are from BCM satellite locations, the mice must be delivered in a cardboard box (provided by CCM) or transferred by CCM.
- The core will collect sperm and cryopreserve in 9 straws (fewer straws if there is only one male).
- Quality assessment will be performed via IVF using sperm from 1 straw. The fertilization rate is calculated by the percentage of 2-cell stage embryos after overnight incubation.
The core will store the cryopreserved sperm in our liquid nitrogen tank up to one year. Investigators will need to coordinate the transfer of the cryo stock of their mouse lines to a commercial company for long-term storage
What is expected
- Generally, 9 straws of cryopreserved sperm will be produced.
- Quality control is completed for each mouse line preserved. A fertilization rate of 20% or above is a passing rate for our QC.
- If the QC test does not pass our standard, the core offers to repeat the cryopreservation at 50% cost.
- If a reproductive defect is known for the specific GEM model, the total number of straws produced, and sperm quality could be low. In such an instance, additional cryopreservation attempts will be done at 100% cost.
- Males older than 7 months of age can be provided for sperm cryopreservation in extreme circumstances. Please contact the core if this needs to occur. However, if sperm number or quality is determined to be low, the core will not repeat the cryopreservation at a reduced cost