Reliable recovery of inbred mouse lines using cryopreserved spermatozoa

Since the mouse has become the most detailed model system to investigate th e genetics and pathogenesis of human diseases, large numbers of new mouse s trains have and continue to be produced. In nearly all animal facilities, t he maintenance of breeding colonies is limited and mouse strains have to be archived in an efficient way. This study was undertaken to test the reliab ility of recovering mouse lines by use of cryopreserved spermatozoa from in dividual male mice. In contrast to many studies, spermatozoa and oocytes we re derived from the same genetic background. 30 C3HeB/FeJ males belonging t o three different categories (wild-type, F1-generation of ENU-treated males , and defined mutants) were recovered by producing at least 20 offspring fr om each donor. Independent of the experimental group, every single male was successfully recovered. Archiving mouse strains by cryopreservation of spe rmatozoa may, therefore, offer a reliable way to preserve genetically valua ble mouse strains and provides an efficient management strategy for animal facilities.