Decontamination of genetically modified mice strains by embryo transfer for obtaining SPF colonies in a Brazilian animal facility

• Main Authors: Ana Tada Fonseca Brasil Antiorio, Sílvia Maria Gomes Massironi, Rosália Regina de Luca, Márcio Augusto Caldas Rocha Carvalho, Vanessa Yamamoto Tambellini, Danilo Wadt, Juliana Bortolatto, Joana Bom, Claudia Madalena Cabrera Mori
• Format: Article
• Language: English
• Published: Universidade de São Paulo 2019-06-01
• Series: Brazilian Journal of Veterinary Research and Animal Science
• Subjects: Strains rederivation; Animal reception; Cleaning colonies; Assisted reproduction; Mouse embryos
• Online Access: http://www.revistas.usp.br/bjvras/article/view/143588

The introduction of new strains of mice in specific pathogen-free (SPF) animal facilities should be performed carefully to avoid breaking sanitary barriers. To meet this need, animals should be rederived to reduce infection risk and thus avoid research interference caused by loss of animal health status and welfare. The objective of this study was to implement mice embryo transfer in the laboratory mouse facility of the Department of Immunology at the Institute of Biomedical Sciences/University of São Paulo, Brazil. Embryo transfers were performed to rederive genetically modified mouse strains with undefined sanitary status, received from different research and educational institutions. Fertilized eggs at two-cell stage were obtained by natural means and transferred into the oviducts of SPF pseudo-pregnant female mice. All surgical procedures were performed under aseptic conditions. A total of 625 embryos were transferred into the recipients. 148 pups were born, of which 140 were reared. Viruses, bacteria and intestinal protozoa were eliminated using this technique. The improvement in the microbiological status of mice allowed their expansion in our SPF facility. With these results, we can stimulate the use of embryo transfer technique between rodent facilities in Brazil and thus encourage the distribution of better models to our scientific community.