One-step vitrification of murine embryos redefines cryopreservation standards

Cryopreservation of embryos is amongst the most powerful and efficient tools for indefinitely preserving the genetics of laboratory animals. The ensuing benefits are numerous and include reduction of costs associated to strain perpetuation, limitation of mutations occurrence and spreading, ease and safety of transnational shipping, and reduction of live animal husbandry. It has been demonstrated that vitrification is more efficient than slow freezing in human assisted reproduction, where it stands now as the gold standard. This is equally true for murine embryos, where vitrification has been shown to better preserve chromatin integrity, induce lower intracellular ingress of cryoprotectants and ultimately yield better embryo survival and development than slow freezing. Beside these benefits, current vitrification procedures require multiple pre-cooling and post-warming exposure steps to dedicated solutions to reach maximum effectiveness, which appears difficult to deal with when many embryos must be cryopreserved in one single session. We have developed and patented a unique one-step embryo vitrification procedure which is as efficient as the best multi-step vitrification methods. Moreover, our media are chemically defined (no serum nor undefined biological component), and aseptic vitrification carriers can be used without any yield loss. Our one-step vitrification kits and media for rodents (VitriMice™, VitriCell) address the poor ergonomy issues of classical vitrification, providing scientists with efficient, biologically safe and user-friendly solutions for embryo cryopreservation. Consequently, our one-step vitrification technology improves efficiency and applicability of cryopreservation for laboratory rodents, thereby contributing to the reduction of the number of live animals required to perpetuate and spread useful strains and colonies.