Recovery of Oocytes from Bovine Ovarian Tissue Transplanted in Nod Scid Mice

Journal of Animal and Veterinary Advances 01/2004; DOI: 10.1016/S0015-0282(01)02182-3
Source: DOAJ

ABSTRACT Hormonal stimulation following xenografting of ovarian tissue into immunodeficient mice promoted antral follicle development. Efficient retrieval of oocytes contained in these antral follicles is crucial in implementing a protocol involving xenotransplantation for fertility preservation of cancer patients. Using a bovine model, our objective was to recover oocytes from calf ovarian tissue transplanted into immunodeficient mice. Fresh pieces of ovarian cortex, 1-2 mm3, from calves were placed in subcutaneous spaces of male NOD SCID mice. Hormonal treatments were initiated 3 days after surgery. Control mice (n=3) received saline while treated mice (n=4/group) received daily intraperitoneal injections of either 4 IU of FSH plus 4 IU of LH, 4 IU of FSH or 1 IU of FSH for 14 days. Forty eight to 72 h after the last injection, mice were euthanized and ovarian grafts were recovered. Serial sections of hematoxylin and eosin stained grafts were used for classifying and counting follicles. Randomly selected unstained ovarian sections were immunostained for nuclear proliferation antigen to ascertain viability. Other grafts were used for oocyte retrieval. Recovered oocytes were stained with orcein to assess maturation. Recovery of grafts (%) was no different across treatment groups. Treatment with FSH plus LH enhanced follicular development, but did not improve oocyte recovery. Evidence of maturation was only observed after incubation in vitro. We conclude that oocytes can be retrieved from xenotransplanted bovine ovarian tissue.