Whole sheep ovary cryopreservation: evaluation of a slow freezing protocol with dimethylsulphoxide.

To evaluate a slow freezing method for whole ovary cryopreservation by evaluating effects of added cryoprotectant. Sheep ovaries were isolated during surgery, flushed with either Ringer-Acetate or dimethylsulphoxide and cryopreserved by slow freezing. After rapid thawing, viability was assessed by ovarian in vitro perfusion, cell culture, histology and fluorescent live-dead assay. Production of cyclic AMP and progesterone was slightly higher in the dimethylsulphoxide group. Cultured ovarian cells from dimethylsulphoxide-preserved ovaries secreted larger amounts of progesterone than cells from Ringer-Acetate preserved. Light microscopy of ovarian biopsies obtained after perfusion, revealed well-preserved tissue in the dimethysulphoxide group but not in the Ringer-Acetate group. The density of small follicles and ovarian cell viability were higher in dimethysulphoxide ovaries compared to Ringer-Acetate ovaries. Equilibrium with its protective effect can be achieved by slow freezing protocol, with an additional protective effect by the presence of dimethylsulphoxide.