Glucose/lactate metabolism of cryopreserved intact bovine ovaries as a novel quantitative marker to assess tissue cryodamage.

ABSTRACT

For some patients, the autotransplantation of a cryopreserved-thawed intact ovary might be the best option to preserve their reproductive potential after fertility-threatening treatment. The best procedure to successfully cryopreserve a human ovary without inflicting a devastating level of cryodamage is to date unknown. To optimize this procedure, this study developed an assay to monitor the extent of cryodamage inflicted on bovine ovarian tissue by different cryopreservation protocols. The assay measures glucose and lactate metabolism of ovarian tissue fragments in vitro and determines the extent of cryodamage in cryopreserved ovaries. This study tested the cryoprotective effect of two different routes of administration of the cryoprotectant dimethylsulphoxide (DMSO). The cryoprotective effect was assessed in different tissue layers of the ovary, namely the cortex, the subcortex and the medulla. Submersion of intact ovaries in DMSO prior to freezing-thawing resulted in the complete protection of the glucose/lactate metabolism of the cortex, but not of the inner ovarian mass. Perfusion without simultaneous submersion, resulted in partial protection of cortex, subcortex and medulla, while the combination of submersion and perfusion conveyed the highest level of protection for all three ovarian tissue layers.