RESUMEN
<p><b>AIM</b>To isolate and transplant germ cells from adult mouse testes for transplantation.</p><p><b>METHODS</b>In order to distinguish transplanted cells from endogenous cells of recipients, donor transgenic mice expressing green fluorescent protein (GFP) were used. Germ cells were collected from the donors at 10-12 weeks of age and spermatogonia were concentrated by percoll fractionation and transplanted into recipient seminiferous tubules that had been previously treated with busulfan at 5 weeks of age to remove the endogenous spermatogenic cells.</p><p><b>RESULTS</b>Twenty weeks after the transplantation, a wide spread GFP signal was observed in the recipient seminiferous tubules. The presence of spermatogenesis and spermatozoa was confirmed in sections of 12 out of 14 testes transplanted (86 %). However, when germ cells were transplanted without concentration the success rate was zero (0/9).</p><p><b>CONCLUSION</b>Germ cells from adult mouse testes can be successfully transplanted into recipient seminiferous tubules if the cell population is rich in spermatogonia and the percoll fractionation is useful in obtaining such a cell population.</p>