Fertility of mice following receipt of ovaries slow cooled in dimethyl sulphoxide or ethylene glycol is largely independent of cyropreservation equilibration time and temperature

Cryopreservation procedures generally depend on both the cryoprotectant used and the equilibration conditions to which the material is exposed. The aim of the present study was to examine the effect of cryoprotectants (dimethyl sulphoxide (DMSO) and ethylene glycol (EG)) and equilibration conditions (0, 30 or 120 min at 0°C or 120 min at room temperature) on the fertility of mice receiving cryopreserved mouse ovaries. The study compared the fertility of cryopreserved Day 14 mouse pup ovaries following grafting to adult recipient mice for 4 months. There was no effect of the cryoprotectant or equilibration condition used on the interval to the first plugging/mating or on the interval to the birth of the first litter, the size of litters, the number of litters produced or the total number of offspring produced. Despite this, when compared with control females (untreated, sham and fresh transplant) the cryopreservation and transplantation procedures delayed fertility. However, the size of litters was equivalent for all cryopreserved and control groups (P > 0.05). The results show that, for the equilibration conditions examined, DMSO and EG are equally efficient cryoprotective agents for mouse ovarian tissue.