Histological evaluation of the effects of cryopreservation in bovine ovarian tissue.

The aim of this study was to show the effects of freezing and thawing in bovine ovarian tissue by histological analysis. Ten cortical slices (2-4 mm in diameter) were obtained from each ovary by tru-cut biopsy and randomly divided into two groups: five fragments were immediately processed as a fresh tissue control group, while the remaining 5 fragments were slowly frozen using DMSO plus sucrose as cryoprotectors, then stored for two weeks and quickly thawed. Histological examination of all cryopreserved ovarian fragments showed no damage in the structure of the organ. Furthermore, there was no difference in the average number of primordial and primary follicles between the two groups of ovarian tissue. These data suggest that the bovine ovary can be used as a suitable model to test new freezing and thawing procedures in search for a standard protocol of human ovary cryopreservation.