Germ cell survival and differentiation after xenotransplantation of testis tissue from three endangered species: Iberian lynx (Lynx pardinus), Cuvier's gazelle (Gazella cuvieri) and Mohor gazelle (G. dama mhorr)

Abstract

The use of assisted reproductive techniques for endangered species is a major goal for conservation. One of these techniques, testis tissue xenografting, allows for the development of spermatozoa from animals that die before reaching sexual maturity. To assess the potential use of this technique with endangered species, testis tissue from six Iberian lynxes (one fetus, two perinatal cubs, two 6-month-old and one 2-year-old lynx), two Cuvier’s gazelle fetuses and one 8-month-old Mohor gazelle were transplanted ectopically into nude mice. Tissue from the lynx fetus, perinatal cubs and 2-year-old donors degenerated, whereas spermatogonia were present in 15% of seminiferous tubules more than 70 weeks after grafting in transplanted testis tissue from 6-month-old donors. Seminal vesicle weights (indicative of testosterone production) increased over time in mice transplanted with tissue from 6-month-old lynxes. Progression of spermatogenesis was observed in xenografts from gazelles and was donor age dependent. Tissue from Cuvier’s gazelle fetuses contained spermatocytes 40 weeks after grafting. Finally, round spermatids were found 28 weeks after transplantation in grafts from the 8-month-old Mohor gazelle. This is the first time that xenotransplantation of testicular tissue has been performed with an endangered felid and the first successful xenotransplantation in an endangered species. Our results open important options for the preservation of biological diversity.

Targeted Germline Modifications in Rats Using CRISPR/Cas9 and Spermatogonial Stem Cells

“…Spermatogonial gene editing using CRISPR/Cas9 technology can readily be adopted in rodents on a scalable level (Izsvak et al, 2010; Kanatsu-Shinohara et al, 2005; Nagano et al, 2001a), and could be established to streamline pure mutant animal production in other applied species important for science, industry, conservation and medicine (Arregui et al, 2013; Hermann et al, 2012; Nagano et al, 2001b; Zeng et al, 2013). Indeed, proof-of-concept for correcting genetic disease in mice by spermatogonial gene editing with CRISPR/Cas9 was reported during revision of this manuscript (Wu et al, 2014).…”

Research on reproduction is essential for captive breeding of endangered carnivore species

“…Biobanking of ovarian and testicular tissues from Iberian lynx killed in road accidents (Roldan et al., ) or died within the breeding programme was conducted from the very beginning of the conservation breeding programme. Tissue can be cryopreserved for future use in xenotransplantation (Arregui, Dobrinski, & Roldan, ). Recently, two females from the conservation breeding programme were ovariohysterectomized due to medical indications.…”

Xenografting of testicular tissue pieces: 12 years of an in vivo spermatogenesis system

“…Bovine and gazelle fresh foetal tissue survived and spermatogenesis proceeded to the spermatocyte stage 10 and 15 months post-grafting respectively (Rodriguez-Sosa et al . 2011, Arregui et al . 2013) while haploid germ cell are found at similar time point with young bovine testicular xenografts (Rathi et al .…”

“…Also, survival is lower in immunocompromised mice than in wild type and although some studies kept mice for more than a year (Honaramooz et al . 2002b, Arregui et al . 2013) most of them commented that some mice became ill or died before the selected time point for sacrifice (Snedaker et al .…”

“…Spermatogonia but no differentiated germ cells were found in Iberian lynx testis grafts more than one year post-grafting, spermatocytes were present in Javan Banteng and Cuvier´s gazelle grafts while xenografted tissue from Mohor gazelles contained round spermatids (Honaramooz et al . 2005, Arregui et al . 2013).…”