Follicular development in cryopreserved marmoset ovarian tissue after transplantation

Pieces of marmoset ovary were frozen by slow cooling in 1.5 M dimethylsulphoxide. The follicles in fresh and frozen tissue were counted and examined for morphological appearance in stained serial sections. The proportion of normal follicles was similar in fresh tissue and frozen tissue examined immediately after thawing. Follicles at all stages of folliculogenesis up to the small antral stage survived freezing and thawing. Fresh and frozen tissue was transplanted underneath the kidney capsules of ovariectomized immunodeficient mice. The establishment of grafts was similar, and oestrogenic activity (cornification of the vaginal epithelium) was observed in the recipients 20 and 16 days after transplantation of fresh and frozen grafts respectively. The total number of follicles and the proportion of normal follicles were similar in fresh and frozen grafts. Grafts of frozen tissue recovered between 7 and 15 days after transfer contained follicles up to the small antral stage of development. Grafts recovered between 21 and 32 days contained follicles at all stages of folliculogenesis, including large antral follicles (1-2 mm diameter). Our results suggest that freezing and thawing do not substantially damage marmoset ovarian tissue, and the cryopreserved tissue retains its ability to support the development of large antral follicles.