Production of the first offspring from oocytes derived from fresh and cryopreserved pre-antral follicles of adult mice

Abstract

Although mammalian ovaries contain hundreds of thousands of pre-antral follicles, fewer than 1% of these reach maturity and ovulation. Obtaining immature eggs from the pre-antral follicles of ovarian tissue could increase the possibility of preserving fertility in women undergoing anti-cancer treatment, and in women who wish to delay pregnancy and child raising until they are older. This study reports the birth of 10 healthy mouse pups derived from oocytes obtained from pre-antral follicles after adult ovary tissue cryopreservation and allotransplantation. High in-vitro maturation (55.1%), fertilization (76.3%) and cleavage (98.3%) rates were achieved using these oocytes, and there was no significant difference between the vitrified and control samples except in maturation rate (55.1 versus 72.8%, P < 0.05). After an ultra-rapid vitrification procedure, the warmed tissue fragments were transplanted beneath the kidney capsule of severe combined immunodeficient mice for onward in-vivo culture. Within 10 days of culture, 138 full size oocytes developed from the 456 transplanted pre-antral follicles. In-vivo growth of follicles was followed by in-vitro oocyte maturation, in-vitro fertilization and subsequent embryo transfer, leading to the birth of 10 healthy pups. These results may lead to increasing the possibility of preserving fertility by cryopreservation of ovarian tissue.

Successful in vitro culture of pre-antral follicles derived from vitrified murine ovarian tissue: oocyte maturation, fertilization, and live births

“…Live offspring have been reported after transplantation of vitrifiedwarmed ovarian tissue into newborn or adult mice (Hani et al 2006, Kagawa et al 2007. Until now, however, the production of live offspring from primordial and pre-antral follicles from cryopreserved/thawed ovarian tissue and cultured to mature in vitro has only been reported in immature mice (Liu et al 2001, O'Brien et al 2003, Hasegawa et al 2006.…”

Live offspring from vitrified blastocysts derived from fresh and cryopreserved ovarian tissue grafts of adult mice

“…Some successes have been reported by maturing oocytes in vitro (Liu et al 2001) or in vivo (Snow et al 2004) from cryopreserved ovaries from immature mice. However, the success for mature adult mice is still limited , Kagawa et al 2007). The ovaries of adult mice have more collagen fiber compared with those of immature mice, making them relatively harder and difficult to revascularize quickly after transplantation (Kagawa et al 2007), fibrous connective tissue might also affect the permeability of cryoprotectant, compromising the tissue recovery after cryopreservation procedures.…”

“…Vitrification is a process which aims to transform intraand extracellular fluids into a glass-like matrix without forming ice crystals. It is faster than slow-cooling and can be an effective method for cryopreserving ovarian tissue (Chen et al 2006, Kagawa et al 2007, Li et al 2007. High concentrations of cryoprotectant and fast cooling rates are the most important elements in achieving vitrification.…”

“…In the mouse grafting model, healthy pups have been reported from F-COCs retrieved from fresh or cryopreserved ovarian grafts (Kagawa et al 2007) while no attention has been drawn to those N-COCs or P-COCs. However, such selective criteria cannot always be used clinically, because the main aim is to maximize the number of matured oocytes for fertilization in vitro.…”

Review on Ovarian Cryopreservation in Large Animals and Non-Human Primates

“…In this study, vitrification was performed using the Cryotissue method (Kagawa et al, 2007), where the ovarian cortex was positioned on a thin metal strip that was plunged into liquid nitrogen (LN) and inserted into a protective container for storage in LN. Rapid post-thaw warming was done with immersion of the metal strip into TCM-199, supplemented with sucrose at 40ºC followed by washing in the identical solution but with decreasing sucrose concentration.…”