Development of strips of ovine testes after xenografting under the skin of mice and co-transplantation of exogenous spermatogonia with grafts

Abstract

Xenografting of testicular tissue is an attractive new strategy for studying postnatal development of spermatogenesis and to preserve male genetics in large mammals. Typically, small cubes of immature testis (1 mm 3 ) are grafted under the dorsal skin of immune-deficient mice. We attempted to increase the total number of seminiferous tubules in each xenograft with spermatogenesis by grafting flat strips of testis (w9!5!1 mm) from ram lambs in immune-deficient mice. The percentage of grafts that survived and percentage of seminiferous tubules that developed spermatogenesis were the same as those reported after xenografting small cubes of lamb testis. Partially purified sheep spermatogonia were labeled with the fluorescent dye carboxy fluorescein diacetate succinyl diester and transplanted into the seminiferous tubules of one of the donor testis just before engraftment. The temporary label in the donor cells was detected for 4 weeks after xenografting, suggesting that co-engraftment of spermatogonia with testicular tissue may be a way to rapidly determine the effect of a specific gene on spermatogenesis. Finally, Sertoli cell lesions in xenografts of lamb testes were quantified, and their number and severity were found to increase, especially after grafts had been in place for 4 weeks. Although this coincided with the development of spermatogenesis, the extent of germ cell differentiation negatively correlated with severity of the lesions.

Spermatogonial stem cell regulation and spermatogenesis

“…2007; Arregui et al . 2008; Rodriguez-Sosa et al . 2010) and may allow germline preservation for endangered species or valuable domestic strains.…”

The Number of Grafted Fragments Affects the Outcome of Testis Tissue Xenografting from Piglets into Recipient Mice

“…In a recent report of testis tissue xenografting using donor lambs [26], two flat strips of testis tissue (~9 × 5 × 1 mm or ~45 mm 3 each) were grafted per recipient mouse and recovered after 4 months resulting in a growth of 2.4-fold in the size of grafts. Although in the latter study a direct comparison with the conventional size of testis fragments was not made, it may be deduced that the relative physical growth of the flat stripes of testis tissue per mm 3 was much less than that of cube fragments used in our study.…”

Genome Banking for Vertebrates Wildlife Conservation

“…Other alternatives that have been proposed are to mince the tissue and then suspend it in freezing extender to achieve better cryoprotection (Crabbe et al, 1999) or to cut the testicular tissue into thin stripes (e.g. ~9×5×1 mm in sheep) to increase the total number of seminiferous tubules in each graft (Rodriguez-Sosa et al, 2010). Although such tissue samples can be obtained from every individual, infant, juvenile or adult, almost all successful studies to date used immature tissue (Ehmcke & Schlatt, 2008).…”