Germ cell transfer into rat, bovine, monkey and human testes

Germ cell transplantation is a potentially valuable technique offering onco logical patients gonadal protection by reinitiating spermatogenesis from st em cells which were reinfused into the seminiferous tubules. In order to ac hieve an intratubular germ cell transfer, intratubular microinjection, effe rent duct injections and rete testis injections were applied on dissected t estes of four different species: rat, bull, monkey and man. Ultrasound-guid ed intratesticular rete testis injection was the best and least invasive in jection technique with maximal infusion efficiency for larger testes. Deep infiltration of seminiferous tubules was only achieved in immature or parti ally regressed testes. This technique was applied in vivo on two cynomolgus monkeys. In the first monkey a deep infusion of injected cells and dye int o the lumen of the seminiferous tubules was achieved. Tn the second, transp lanted germ cells were present in the seminiferous epithelium 4 weeks after the transfer. These cells were morphologically identified as B-spermatogon ia and located at the base of the seminiferous epithelium. In summary, this paper describes a promising approach for germ cell infusion into large tes tes. The application of this technique is the first successful attempt of a germ cell transfer in a primate.