Male germ cell transplantation: an experimental approach with a clinical perspective.

Germ cell transplantation was developed in strains of mice. The infusion of germ cell preparations into the seminiferous tubules of infertile hosts led to repopulation of the testis with donor germ cells and restored fertility. Meanwhile, this technique has become a powerful tool to study the expansion of the testicular stem cell population and the kinetics of spermatogonial proliferation and re-induction of spermatogenesis. Further approaches, such as the transfer of rat/hamster/rabbit germ cells into mouse testes or cryopreservation or culture of spermatogonia, have widened the spectrum of applications associated with germ cell transplantation. Since the devastating effects of chemo- or radiotherapy on spermatogonia are the cause of infertility in oncological patients, germ cell transplantation might become an alternative approach for gonadal protection in prepubertal and postpubertal male tumour patients. This review focusses on recent developments with respect to germ cell transplantation and highlights the problems and perspectives of future clinical applications.