Optimization of protocols for human ovarian tissue cryopreservation with sucrose, 1,2-propanediol and human serum

Chemotherapy/radiotherapy protocols have improved the long-term survival of cancer patients. Frequent consequences of antiblastic treatments, used to eradicate malignancies, are the partial or total loss of ovarian function, which in children and women of a fertile age can result in permanent sterility. Ovarian tissue or oocyte cryopreservation implemented before the beginning of the therapies may potentially restore fertility in children and women. The thawed ovarian tissue can be transplanted orthotopically at the ovarian peduncle of origin in order to restore both gametogenic and steroidogenic functionality, theoretically leading to the resumption of the menstrual cycle and natural conception. Alternatively tissue can be transplanted heterotopically, in sites which are particularly vascularized (under the omental bursa, under the renal capsule, on the surface of the deltoid muscle and on the anterior surface of the uterus) with the aim of restoring the gametogenic and steroidogenic function. The aim of this study was to examine the effect of different concentrations of 1,2-propanediol (permeating cryoprotectant), sucrose (non-permeating cryoprotectant) and human serum as protein support, in the cryopreservation solution on human ovarian tissue preservation after freezing-thawing. Biopsies of ovarian cortex were obtained from 13 patients. All specimens were cryopreserved using a slow freezing-rapid thawing method in different cryopreserving solutions. The tests were conducted using light and transmission electron microscopy. Results showed that the cryo-damage occurs predominantly in the stromal and follicular cells. The best preservation of morphological characteristics was obtained using the freezing-thawing protocol which concentrations of cryoprotectants and human serum are among the lowest.