Progress on Optimal Protocols of Ovarian Tissue Cryopreservation

As the advances in treatment of neoplasia, the protection of female fertility is attaching more and more attention. The application of embryo cryopreservation in IVF center brings definite benefits to some patients. However, there are limitations in embryo cryopreservation. The ovarian tissue cryopreservation is a new research area, in which the cryopreservation technology is the first problem. Two ways of ovarian tissue cryopreservation are slow freezing and vitrification. Compared with the freezing ways using in the piece of ovarian tissue,the directional freezing is a preponderant method for the whole ovary. The directional freezing can keep the whole ovary at the same cooling rate, which is thought to reduce the injury during the whole cooling process.Different freezing protocols have different effects on functional recovery of the frozen-thawed ovarian tissue. It is important to explore the suitable and standard protocol to optimize the efficiency of cryopreservation. Those optimal protocols of ovarian tissue cryopreservation were discussed in this review, so as to provide some references for clinical practice.