Sperm factories get under the skin

The grafting of testicular tissue from one rodent to another has been possible for some time, but in other mammalian species this procedure has proven difficult to achieve beyond spermatogonial proliferation — probably owing to the incompatibility of microenvironments. In August 15 Nature Ali Honaramooz and colleagues from University of Pennsylvania, US show that complete spermatogenesis can be established by grafting testis tissue from various newborn mammals under the skin of mouse hosts (Nature 2002, 418:778-781).

Honaramooz et al. inserted fragments of testicular tissue (0.5–1mm³) from neonatal mice, pigs or goats under the back skin of castrated immunodeficient mice. They observed that after 2-4 weeks more than 60% of the neonatal testicular grafts from all three donor species survived and increased in volume. In addition, they showed that sperm recovered from testis grafts of all three species into mice were viable and functional.

"Grafting of...