Endocrine Abstracts

Objective: Ovarian cryopreservation is an emerging technique that may advance breeding of endangered species and preservation of reproductive capacity in young women cancer patients who will undergo chemo/radiotherapy destruction of ovarian tissue.

Materials and methods: A total of twelve mature female rabbits were used in experiment. Rabbits were anesthetized and then subjected to laparotomy. Bilateral oophorectomy was used to save one ovary as fresh control and the other as experiment in each rabbit. The ovary to be experimented was isolated with retained ovarian vessels 2.5 cm from the ovarian hilum and embedded in a wedge of mesenteric fat after dissection of soft tissue and ligation of peripheral vascular connections. The ovarian artery was cannulated and perfused with cryoprotectant. The freezing protocol was based on a slow freezing rate to store intact ovary at −196  °C and rapid thawing rate by perfusion cryoprotectant (CPA) of 1.5 M dimethylsulfoxide (DMSO) and reversal concentration gradient respectively. Each rabbit was grafted one intact cryopreserved ovary in groin area by vascular anastomosis. Ovarian function was evaluated by vaginal cytology, hormone assays and ovarian biopsy until 6 months later.

Results: Fully 83.3% of rabbits had ovarian function as shortly as one week after transplantation. Mean survival rate of primordial follicles is 74.9±4.5% after whole ovarian cryopreservation and 6 month post-transplantation. Cases of failure to regain ovarian function showed cracking of mesenteric fat after ovarian freezing, in contrast to functional ovaries, which had intact mesenteric fat. Cracking of mesenteric fat after the freezing process seems to affect the architecture of the graft complex and thus may be used to predict adverse freezing outcome.

Conclusions: By microvascular manipulation and anastomosis, cryopreservation of an intact ovary followed by transplantation may overcome revascularized ischemia and last reasonable graft longevity, which supports the promising role of whole ovarian cryopreservation.