Contact Clay Douglas Rouse for more information.

Rederivation Services

Pathogens threaten the health status of animal colonies, have a negative effect on research results, and can affect ability to receive or export animals. To produce Specific Pathogen Free (SPF) rodents, our core can utilize both embryo transfer and in-vitro fertilization (IVF).

Embryo Transfer

Ideal for most lines, especially inbred and homozygous lines. Preimplantation embryos are washed and transferred to SPF pseudopregnant recipient females. Recipient females are submitted for serological testing upon weaning of pups to ensure health status.

Due to variability among strains and hormone responsiveness, core cannot guarantee embryo yield or embryo viability.

     Investigator Responsibility:

• Submit a Rederivation Request Form.

• Contact core for scheduling.

• Provide core with approximately 5 males and 5 females (donors). This number may vary depending on strain and investigator needs.

• Males should be proven breeders between 2-8 months of age, singly housed and rested for 1 week.

• Females ideally should be 3 - 4 weeks of age, but older females may be used if discussed with core prior to start of rederivation.

Identification cards will be provided to investigators by the core to be placed on cages. Date of birth, genetic background, and genotype must be provided. Please make core aware of any prior fertility issues and embryonic or neonatal lethality.

     Core Responsibility:

• Superovulate and mate donor mice at current housed location.

• Dissect oviducts at current housed location and transport to lab for harvest and washing.

• Embryos are washed, graded and transferred into SPF recipient females.

• Surrogate dams are housed in rederivation quarantine until pups are born, weaned and dams are serologically tested.

• Tail biopsies will be performed before 21 days and sent to investigator for genotyping, or genotyped by core.

• Negative animals will be returned to investigator or transferred to breeding core.

In-Vitro Fertilization (IVF)

Ideal to recover lines from frozen sperm, lines in which males repeatedly fail to mate normally, or lines that are down to critical numbers. Can also be utilized for heterozygous lines in which the males are to be bred with wild type females. Epididymal sperm is collected from male and used to fertilize oocytes from wild-type females. Two cell embryos are transferred to SPF pseudopregnant recipient females. Recipient females are submitted for serological testing upon weaning of pups to ensure health status. Embryos can alternatively be cryopreserved.

Due to variability among strains and hormone responsiveness, core cannot guarantee embryo yield or embryo viability.

     Investigator Responsibility:

• Submit a Rederivation Request Form.

• Contact core for scheduling.

• Provide core with 2 males or frozen sperm in liquid N2.

• Males should be proven breeders between 2-8 months of age, singly housed and rested for 1 week. Older males may be used if discussed with core prior to start of rederivation.

Identification cards will be provided to investigators by the core to be placed on cages. Date of birth, genetic background, and genotype must be provided. Please make core aware of any prior fertility issues.

     Core Responsibility:

• Provide and superovulate wild-type donor female mice.

• Dissect cauda epididymides at current housed location and transport to lab for sperm harvest or thaw frozen sperm.

• Sperm is incubated overnight with oocytes for fertilization and two cell embryos are transferred into SPF recipient females.

• Surrogate dams are housed in rederivation quarantine until pups are born, weaned and dams are serologically tested.

• Tail biopsies will be performed before 21 days and sent to investigator for genotyping, or genotyped by core.

• Negative animals will be returned to investigator or transferred to breeding core.

Frozen Embryos Recovery

Embryos previously frozen are thawed and transferred to SPF pseudopregnant recipient females. Recipient females are submitted for serological testing upon weaning of pups to ensure health status.

     Investigator Responsibility:

• Submit a Rederivation Request Form.

• Contact core for scheduling.

• Deliver frozen embryos to core which will be stored in liquid nitrogen until implantation.

• Provide Core with detailed freezing and thawing instructions from shipping institution.

    Core Responsibility:

• Embryos are thawed, graded and transferred into SPF recipient females.

• Surrogate dams are housed in rederivation quarantine until pups are born, weaned and dams are serologically tested.

• Tail biopsies will be performed before 21 days and sent to investigator for genotyping or genotyped by core.

• Negative animals will be transferred to investigator or transferred to breeding core.

Genotyping

    Genotyping by Polymerase Chain Reaction (PCR) is available for rederived litters. Please provide primers and conditions.