Damage to fetal XXXX ovarian tissue caused by cryoprotectant exposure and vitrification is mitigated during tissue culture.

@entity1 @entity969 @entity8788 @entity291
PURPOSE: The objective of this study is to characterize the impact of exposure to cryoprotectants followed by vitrification on primordial follicle survival and activation using a fetal @entity291 model. METHODS: In the first study, fetal @entity291 cortical pieces were exposed to cryoprotectants with or without @entity969 and cultured up to 7  days in the presence or absence of @entity8788 . In the second study, cortical pieces were exposed to cryoprotectants with or without @entity969 , vitrified, and cultured up to 7  days after warming in the presence or absence of @entity8788 . Viability and morphology of follicles, as well as proliferation and/or DNA repair in ovarian tissue were analyzed. RESULTS: When compared to non-exposed controls, normal follicular morphology was affected in groups exposed to cryoprotectants only immediately post-exposure and after 1  day of culture, but improved by day 3 and did not significantly differ by day 7. Similarly, normal follicular morphology was compromised in vitrified groups after warming and on day 1 compared to controls, but improved by days 3 and 7. Proliferation and/or DNA repair in ovarian tissue was not affected by vitrification in this model. Cryoprotectant exposure and vitrification of ovarian tissue did not impair the activation of primordial follicles in response to @entity8788 , although activation was delayed relative to non-exposed controls. Interestingly, @entity969 had no noticeable protective effect. CONCLUSION: Vitrified fetal @entity291 ovarian tissue has the intrinsic capacity to mitigate the immediate damage to primordial follicles' morphology and retains the capacity to activate. These findings provide a basis for a successful cryopreservation protocol for ovarian cortical tissue in other species including @entity1 .
