Xenografting of gonadal tissues into mice as a possible method for conservation and utilization of porcine genetic resources


Kazuhiro Kikuchi, Animal Development and Differentialtion Research Unit, Division of Animal Sciences, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan. (Email: kiku@affrc.go.jp)


In vitro production of embryos, including in vitro maturation, fertilization of oocytes and their subsequent culture to the embryo stage, has become the most popular method of studying gametogenesis and embryogenesis in pigs. As well as their utility for basic studies, these procedures now enable us to generate viable embryos and offspring as a means of conserving genetic resources and rare animal breeds. Recently, more advanced technologies such as xenografting of gonadal (testicular and ovarian) tissues into immunodeficient experimental animals have been developed. In combination with in vitro embryo production techniques, this approach may provide many benefits. We have been carrying out studies to acquire basic information about the application of this method to porcine species, and to improve the existing techniques. Recently, we obtained oocytes from ovarian tissue xenografted and grown in nude mice that had the capacity to be fertilized and the ability to develop into early-stage embryos. We also obtained spermatozoa from the xenografted testicular tissues and injected them intracytoplasmically into in vitro-matured oocytes to produce piglets. Here we discuss the further possibilities of conservation and utilization of porcine gonadal tissue by xenografting into immunodeficient mice.