Decontamination of rat embryos and transfer to specific pathogen-free recipients for the production of a breeding colony.

Rouleau, A M; Kovacs, P R; Kunz, H W; Armstrong, D T

When animals are introduced to a specific pathogen-free (SPF) facility, care must be taken to avoid the possibility of disease transmission to the local colony. This study investigated the application of a combination of reproductive biotechnologies to establish a new disease-free colony of two rat strains, DarkAgouti(DA/Pit) and Wistar Furth(WF/Pit), from a stock known to be chronically infected with the following pathogens: Mycoplasma pulmonis, Kilham's rat virus, sialodacryoadenitis/coronavirus, and reovirus type 3. To eliminate the pathogens and optimize the use of animals, superovulation, embryo washing and trypsinization, and embryo transfer were used. Donors (DA/Pit and WF/Pit) were treated as follows: the mature females were synchronized by subcutaneous (s.c.) injection with 40 micrograms luteinizing hormone-releasing hormone agonist/animal on day -4. All immature and mature females were induced to superovulate by continuous s.c. infusion with a commercial porcine follicle-stimulating hormone (FSH) preparation (3.4 or 6.8 mg NIH-FSH-P1 units per day, respectively), beginning on the morning of day -2. On the afternoon of day 0, the animals received 30 IU human chorionic gonadotropin injected intraperitoneally and mated. From a total of 213 ova flushed from the oviducts of 16 programmed donors, 195 transferrable two-cell embryos were recovered. Two outbred strains of SPF rats, Long-Evans (LE) and Wistar (W), were used as recipients. These mature females (LE and W) were synchronized by using luteinizing hormone-releasing hormone agonist as described and made pseudopregnant by cervical stimulation. Two-cell embryos (DA/Pit and WF/Pit) were washed and trypsinized, then transferred to the oviducts of the pseudopregnant recipients (LE and W).(ABSTRACT TRUNCATED AT 250 WORDS)