Allogeneic testes transplanted into partially castrated adult medaka (Oryzias latipes) can produce donor-derived offspring by natural mating over a prolonged period

Abstract

Germ cell transplantation protocols generally require induced immunosuppression in the recipient to avoid rejection of the transplanted cells; cytotoxic drugs may also be used to deprive the recipient germ cells and create a germ cell niche that allows donor-derived germ cells to thrive. In the present study, we demonstrate that in medaka, allogeneic adult testicular tissue will engraft in adult recipients immediately after the rough castration of the recipients and without use of immunosuppressive drugs. The allografted testes are retained in the recipient body for at least three months and are able to produce viable gametes that yield offspring after natural mating. Some recipients showed a high frequency (over 60%) of offspring derived from spermatozoa produced by the transplanted germ cell tissues. Histological analyses showed that allografted testicular tissues included both germ cells and somatic cells that had established within an immunocompetent recipient testis. The relative simplicity of this new approach will benefit investigations of the basic processes of reproductive immunology and will improve the technique of gonadal tissue transplantation.