Introduction

The maintenance of mouse colonies can be expensive and time consuming. Sperm freezing offers the researcher an alternative to maintenance breeding to preserve a mouse line that is not in current use. Sperm freezing also provides a back-up to preserving the line in the unlikely event that the colony becomes pathogen compromised, has a fertility issue or background/genotype is compromised.

When deciding to cryopreserve a line, the Client will need to choose if embryo or sperm freezing is best suited to the strain. Click on here to view a table showing the pros and cons of freezing embryos vs freezing sperm.

Mice Needs

Sperm is collected from a minimum of 3 males from the same strain. This means that the males are sacrificed for the collection of their sperm. The sperm will be pooled unless specifically advised from the client. The males supplied must be of proven fertility. If they are not, additional testing will be conducted by UQBR prior to the sperm cryopreservation at the expense of the client.

Costs

Internal Clients: Free of Charge to UQ researchers

Service includes:

  • Collection and analysis of the sperm
  • Freezing of sperm
  • Administration costs

Additional Costs:            

  • A test thaw for frozen sperm will be done with an IVF. There will be a $165.38 charge to the researcher. This will cover scheduling,  IVF with 2 WT mice, media and embryo culture to blastocyst.
  • Please note it is a condition on UQBR providing the free cryopreservation service only for UQ researchers, that the researcher must pay for the test thaw. A test thaw is the only way to guarantee that a cryopreserved line can be rederived and therefore it is compulsory for each line cryopreserved.
  • If after 2 IVF rounds the cryopreserved sperm is unsuccessful in producing embryos, TASQ will contact researcher about supplying additional mice for further cryopreservation. Test thaw fee is applicable for each round of freezing.
  • Animal agistment of males (contact TASQ for charges).

External client: $518.18

Service includes:

  • Collection and analysis of the sperm
  • Freezing of sperm
  • A test thaw for frozen sperm will be done with an IVF. This involves scheduling, IVF with 2 WT mice, media and embryo culture to blastocyst.
  • Administration costs

Additional Costs:

  • Courier costs to UQ animal facility.
  • Animal agistment of males. Agistment is the weekly charge applied by the animal facilities for the basic care of the animal (contact TASQ for charges).
  • If after 2 IVF rounds the cryopreserved sperm is unsuccessful in producing embryos, TASQ will contact researcher about supplying additional mice for further cryopreservation. Test thaw fee is applicable for each round of freezing.

How to start

  1. Contact TASQ (see Contacts page)
  2. Health reports will need to be sent to TASQ (if applicable)
  3. Download and complete the relevant registration form (UQ internal or external to UQ) and return to TASQ
  4. Once health reports have been reviewed, TASQ will liaise with your animal  facility manager to have the mice shipped to the necessary UQ animal facility.
  5. Sperm freezing will be scheduled with TASQ notifying Client of starting date

Timeline

Week 1

  • Mice are shipped to UQ
  • Sperm collection and analysis
  • Sperm  freezing

Weeks 2-3

  • IVF Test Thaw and analysis
  • Client will be notified of test thaw results after the IVF has been done

* IVF test thaw will be done at the next available IVF timeslot

Additional Notes

  • TASQ will freeze all viable sperm collected. 
  • Additional charges will apply to those lines where males are to be frozen separately
  • TASQ cannot guarantee any mouse strains’ viability after freezing.
  • TASQ registration form must be completed prior to service commencement.
  • Researcher must not cull original colony stock until discussion with TASQ after completion of sperm freezing
  • A current AEC certificate and OGTR number must be supplied prior to commencement of service.  Any AEC renewals or modifications must be submitted to TASQ

Mouse Sperm Cryopreservation section

Cryopreservation Comparison Table - Embryo vs Sperm

The following table demonstrates basic differences between cryopreservation of sperm and embryos.

Embryo Freezing

Gamete (sperm & ovary)

Initial labour

Can take a few months to acquire all the embryos for storage.

Work is done in one day

Initial costs

As charges are dependant on the number of females used, costs will vary for each strain. Is more expensive than gamete freezing

Set cost.

Cheaper than embryo freezing

Numbers cryostored

Het X WT matings= 500

Het x Het matings=300

Homo X WT= 250

Homo X Homo= 250

Collect sperm from 3-5 males, so there are millions

Test thaw

Thaw assesses viability to live births.

Thaw assesses only motility. After freezing/thaw need an IVF session to determine live birth viability. More expensive than embryo freezing

Rederivation

Set cost for rederivation per round. Involves embryo thaw and culture, then an embryo transfer. Cheaper and less labour intensive

Set cost for Mouse IVF per round. Requires donor priming, embryo collection, IVF and culture, then embryo transfer. More expensive and more labour intensive

Genotype/phenotype

When rederived the genotype and phenotype of the resulting progeny will be exactly same as when freezing done.

Only cryopreserves half of genetic make-up of the original strain/background. Future rederivation can only produce a Het (due to IVF with WT eggs).