Direct comparative analysis of conventional and directional freezing for the cryopreservation of whole ovaries
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Application of a Novel Hyaluronan Hydrogel for Three-Dimensional Follicle Culture and Methodology for Mouse Ovarian Follicle Cryopreservation
Published on: May 9, 2025
Sara Maffei1, Maike Hanenberg, Georgia Pennarossa
1Laboratory of Biomedical Embryology, Università degli Studi di Milano, Milan, Italy.
Objective:
To compare conventional slow equilibrium cooling and directional freezing for cryopreservation of whole ovaries.
Design:
Experimental animal study.
Setting:
Academic research environment.
Animal(S):
Adult ewes.
Intervention(S):
Eighty-one ovaries were randomly assigned to fresh control, conventional freezing (CF), and directional freezing (DF) group. Ovaries of CF and DF groups were perfused via the ovarian artery with Leibovitz L-15 medium, 10% fetal bovine serum, and 1.5 M dimethyl sulfoxide for 5 minutes. Each ovary was inserted into a glass test tube containing 10 mL of the same solution and cooled to -100°C or -70°C, respectively. Ovaries were stored in liquid nitrogen for a minimum of 2 weeks.
Main Outcome Measure(S):
Structural integrity of cortical and medulla regions, vascular integrity, follicle in vitro development, cell proliferation, and DNA damage and repair.
Result(S):
All examined parameters indicate that the structure of DF ovaries remains largely intact and comparable to fresh controls, whereas significant damages were observed in CF ovaries.
Conclusion(S):
Directional freezing allows good preservation of whole ovaries, with most of the parameters taken into consideration almost identical to those recorded in fresh control samples. This encourages a reconsideration of the possible use of whole-ovary cryopreservation as a viable alternative to cortical fragments.
