Cryopreservation and culture of human primordial and primary ovarian follicles

Cryopreservation of ovarian cortical tissue containing high numbers of primordial and primary follicles would benefit young women who are going to undergo chemotherapy or radiotherapy, or anticipated premature ovarian failure. Human ovarian tissue has been successfully cryopreserved using dimethyl sulphoxide, propanediol and ethylene glycol as cryoprotectants. The viability after thawing has been shown morphologically, using viability tests, by transplanting the tissue to immunodeficient mice, and by culturing them in vitro. Maturation of oocytes in in vitro cultures from early follicles would be better than replantation for girls with malignancies which could be replanted with the tissue. For the time being we have managed to culture cryopreserved human primordial and primary follicles to secondary, and occasionally to early antral stages in organ culture within slices of cortical tissue in extracellular matrix. The culture conditions have to be improved to get systematically early antral follicles for a second step of maturation of cumulus-oocyte-complexes.