Spermatogenesis in ferret testis xenografts: a new model

Testis xenografting is both a promising tool to study spermatogenesis and a means to preserve the genetic information and reproductive potential of prepubertal male animals. The present study was conducted to evaluate this technique using testis tissue from domestic ferrets, an important biomedical model and a model for the conservation of small carnivore species. Fresh testis tissue from 8-wk-old ferrets was implanted ectopically under the skin on the backs of castrated nude mice and subsequently evaluated for testosterone production and establishment of spermatogenesis at 10, 20, 25, and 30 wk after xenografting. A total of 40% of fresh ferret xenografts were harvested. Seminal vesicles were collected from the recipient mice and weighed as an assay for bioactive testosterone. The weights of seminal vesicles from the mice showed no significant difference from those of uncastrated, control nude mice, indicating that the xenografts were producing physiologically relevant amounts of testosterone. The ferret testis xenografts produced differentiating germ cells and sperm at the same time as did testis from age-matched control ferrets. These data demonstrate the ability of Mustelidae testicular tissue to establish spermatogenesis in nude mice after testis xenografting.