Slow controlled-rate freezing of human in vitro matured oocytes: effects on maturation rate and kinetics and parthenogenetic activation
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Published on: July 10, 2021
Karen Versieren1, Björn Heindryckx, Thomas O'Leary
1Department of Reproductive Medicine, Ghent University Hospital, Ghent, Belgium. karen.versieren@ugent.be
Objective:
To create a pool of frozen donated human oocytes and find the optimal stage for slow controlled-rate freezing of human in vitro matured oocytes.
Design:
Oocytes at different developmental stages of maturation (germinal vesicle, metaphase I, or metaphase II) and oocytes that failed to fertilize after IVF or intracytoplasmic sperm injection (ICSI) were frozen using a slow controlled-rate freezing protocol. Frozen/thawed oocytes were artificially activated to verify activation potential and compared with oocytes that were not frozen.
Setting:
University hospital-based fertility center.
Patient(S):
Stimulated patients undergoing IVF/ICSI treatment donated oocytes left over during their infertility treatment.
Intervention(S):
Human oocytes were frozen at different stages of maturation. Fresh and frozen/thawed oocytes were activated by electrical pulses followed by incubation in 6-dimethylaminopurine.
Main Outcome Measure(S):
Survival rate, maturation rate and kinetics, and activation potential.
Result(S):
Human oocytes at all developmental stages have high survival rates after slow controlled-rate freezing. Frozen/thawed germinal vesicle oocytes showed decreased and delayed maturation after thawing. Activation potential was not affected.
Conclusion(S):
A pool of donated human oocytes could be established using slow controlled-rate freezing. Immature oocytes should be frozen after in vitro maturation.
