Influence of hormone environment and donor age on cryopreserved common wombat (Vombatus ursinus) ovarian tissue xenografted into nude mice

Abstract

Developmentally competent oocytes can be collected from xenografted ovarian tissues; however, optimal xenograft conditions need to be established for this technique to be of use in assisted reproduction. In the present study, common wombat ovarian tissue was xenografted under the kidney capsule of nude mice to clarify the role of recipient gonadal status and donor tissue age on graft establishment, follicle development and oocyte recovery. Eighty-nine per cent of all grafts were recovered; of these, 78% contained growing follicles. In female graft recipients, follicle development to the antral stage occurred earlier in ovariectomised recipients compared with intact graft recipients. Similarly, follicle development occurred earlier in recipients of pouch young ovarian tissue grafts when compared with subadult xenografts. Follicle development proceeded to the antral stage in subadult grafts placed under the kidney capsule of male recipient mice, albeit at a slower rate than subadult grafts placed in female recipients. Oocytes were collected from grafts placed in female and male recipients, but no mature oocytes were observed at the time of collection, nor could these oocytes be matured in vitro. The present study demonstrated that common wombat pouch young tissue xenografted to female recipient mice, and subadult ovarian tissue xenografted to male recipient mice, can develop to the antral stage and can therefore facilitate oocyte collection. However, mature oocytes were not obtained using the current protocol.

Wombat reproduction (Marsupialia; Vombatidae): an update and future directions for the development of artificial breeding technology

“…Later, Cleary et al (2004) showed that: ovarian tissue can develop to the antral stage when xenografted to male recipient mice; removal of the female recipient's ovaries accelerated follicle development and that no follicular growth occurs in xenografted ovarian tissue from PY or subadult CW females. As no oocytes were mature at the time of collection or after a period of IVM, it still remains unclear which conditions are best suited to generating viable oocytes from wombat ovarian xenografts (Cleary et al 2004).…”

Effects of gonadotrophin treatments on meiotic and developmental competence of oocytes in porcine primordial follicles following xenografting to nude mice

“…Snow et al (2002) demonstrated that oocytes that grow within mouse ovarian tissue xenografted to nude rats acquire the ability to generate pups. Ovarian tissues have been prepared from species phylogenetically distant from mice, including humans (Oktay et al 1998, Weissman et al 1999, Kim et al 2002, Gook et al 2003, dogs (Metcalfe et al 2001), monkeys (Candy et al 1995), sheep (Gosden et al 1994), cows (Senbon et al 2003), pigs (Kaneko et al 2003, Kagawa et al 2005, tammar wallaby (Mattiske et al 2002) and common wombats (Cleary et al 2003(Cleary et al , 2004, and xenografted to immunodeficient mice. To our knowledge, only one study (Kaneko et al 2003), in which neonatal pig ovarian tissues were xenografted, has proven that primordial oocytes can develop in the host mice and acquire fertilizing ability in vitro.…”

Mammalian fertility preservation through cryobiology: value of classical comparative studies and the need for new preservation options

“…Similar studies are ongoing in other laboratories, also with encouraging results (Jewgenow et al 2011). For example, high survival of slow frozen–thawed ovarian tissue has been achieved in some felid or marsupial (wombat; Vombatus ursinus ) species on the basis of cell integrity as well as grafting success (Paris et al 2004; Cleary et al 2004; Jewgenow et al 2011). Our laboratory has also started to routinely preserve the female genome from species that are priorities in our conservation breeding programs, including the black-footed ferret, cheetah, clouded leopard ( Neofelis nebulosa ), Eld’s deer ( Rucervus eldii ), scimitar-horned oryx ( Oryx dammah ) and tufted deer ( Elaphodus cephalophus ).…”

“…Yet the information required to achieve these milestones remains rudimentary at best, even for livestock and common laboratory species (Paris et al 2004; Cleary et al 2004; Songsasen et al 2012). For example, it has been projected that it will be necessary to maintain living follicles in culture for up to 6 months to allow the recovery of viable oocytes in carnivores (Songsasen et al 2012).…”