Reducing the use and refining the distribution of male Xenopus

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To understand the normal biological processes in humans and animals, together with the diseases that occur when these go wrong, we need to study "model organisms". In addition to being ethically preferable, there is a long history of research using the models, so we have both a great deal of information about them and a wide range of experimental tools to work with. Two of the four main vertebrate model organisms are aquatic Xenopus frogs that come from Africa. Much of our knowledge about basic animal biology comes from research using Xenopus, including: cell division control, intercellular signaling, cell reprogramming, regeneration and healing, gene control networks and DNA repair. More recently they have been used to study human genetic diseases, more than 90% of human genes are found in Xenopus and the structure of over two-thirds of their genomes is the same.To support the use of model organisms, resource centres make, collect, quality assure and distribute all of the molecular and animal resources needed. For Xenopus the main resource centre is the EXRC, which collaborates closely with centres in the US and Japan to ensure that researchers' needs are met worldwide. Part of the EXRC's mission is to improve the welfare of frogs used for research and this project contributes to that aim. Currently male frogs are sent to research laboratories where they are kept in tanks and then, when embryos for experiments are needed, they are killed humanely and their testes removed to provide the sperm for in vitro fertilization. This has two disadvantages we aim to overcome: first the frogs are stressed by travel and second, because so many embryos are created by one fertilization (often more than can be analysed in an experiment) the removed testes often become inactive before all of the sperm are used, leading to wastage. Together with our collaborators and the US stock centre we have developed robust methods for freezing sperm and recently performed three successful trials of sending male gametes as frozen sperm to researchers based abroad. We now need to develop this process to the point where it can be widely used. To do so we will first test whether we can divide the testes from each male into more than the 8 sections that we currently use, without affecting fertilization rates and the developmental fate of the embryos produced. We will then assess the variability of embryo production from each piece of testis, allowing us to understand how best to quality assure the sperm we send to our users. The next stage of the programme is to develop the distribution process, first by testing different courier's services using dummy packages to a group of 7 labs around the world and optimizing the packaging and paperwork to speed passage through customs. Once we are sure of the delivery process, we will send frozen sperm and discuss the use of these in the test laboratories by Skype. We will use these discussions to improve the written and video instructions that accompany the sperm as more batches are sent out. Once we are consistently distributing frozen sperm to the test laboratories we will then extend the service to all of our users who want it and encourage the other stock centres to do so too. We are confident that users will take up this service due to the substantial cost savings it represents over sending live animals.This programme will deliver a more cost effective way of sending male Xenopus gametes whilst improving animal welfare and decreasing the number of male frogs used.