Human ovarian cryopreservation: vitrification versus slow freezing from histology to gene expression

Abstract

Cryopreservation of ovarian tissue is one of the strategies offered to girls and women needing gonadotoxic treatment to preserve their fertility. The reference method to cryopreserve is slow freezing; vitrification is an alternative method. The aim was to evaluate which of the two is the best method for human ovarian tissue cryopreservation. Each ovary was divided into three groups: (i) fresh; (ii) slow freezing; and (iii) vitrification. An evaluation of the follicular density, quality and the expression six genes (CYP11A, STAR, GDF9, ZP3, CDK2, CDKN1A) were performed. We observed no significant difference in follicular density within these three groups. Slow freezing altered the primordial follicles compared to the fresh tissue (31.8% vs 55.9%, p = 0.046). The expression of genes involved in steroidogenesis varied after cryopreservation compared to the fresh group; CYP11A was under-expressed in slow freezing group (p = 0.01), STAR was under-expressed in the vitrification group (p = 0.01). Regarding the expression of genes involved in cell cycle regulation, CDKN1A was significantly under-expressed in both freezing groups (slow freezing: p = 0.0008; vitrification: p = 0.03). Vitrification had no effect on the histological quality of the follicles at any stage of development compared to fresh tissue. There was no significant difference in gene expression between the two techniques.

Keywords:

• Fertility preservation
• ovarian tissue
• slow freezing
• vitrification
• gene expression
• morphology

Acknowledgments

We thank Philip Robinson (DRCI, Hospices Civils de Lyon) for help in manuscript preparation.

Authors’ contributions

Participation in design (P.J., C.F., E.L., C.S., N.MJ.), data analysis (P.J., E.L., M.B., J.L.), execution and manuscript drafting (P.J., E.L.) and critical discussion (E.L., E.F., B.S., J.L.).

Disclosure statement

Availability of data and materials: The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. The authors declare that they have no competing interests.

Additional information

Funding

This work was supported by the Agence de la Biomédecine under grant [Project No. R18122CC].