Pretreatment of ovaries with collagenase before vitrification keeps the ovarian reserve by maintaining cell-cell adhesion integrity in ovarian follicles

Abstract

the mammalian ovarian follicle is comprised of the germ cell or oocyte surrounded by the somatic cells, the granulosa and theca cells. the ovarian stroma, including the collagen-rich matrix that supports the three-dimensional disk-like follicular structure, impacts the integrity of the ovarian follicle and is essential for follicular development. Maintaining follicular integrity during cryopreservation has remained a limiting factor in preserving ovarian tissues for transplantation because a significant proportion of developed follicles in the frozen-thawed ovaries undergo atresia after transplantation. In this study, we show for the first time that during vitrification of the mouse ovary, the attachment of the oocyte to the granulosa cells was impaired by the loss of the cadherin adhesion molecules. importantly, exposure to a high osmotic solution greatly decreased the ratio of oocyte diameter to the diameter of its follicle but did not alter the collagen-rich matrix surrounding the follicles. By treating ovaries briefly with collagenase before exposure to the hyper-osmotic solution the ratio of oocyte diameter to follicle diameter was maintained, and cadherin adhesion junctions were preserved. When frozen-thawed ovaries were transplanted to the bursa of recipient hosts, pretreatment with collagenase significantly increased serum levels of AMH, the number of intact follicles and the total number of viable offspring compared to frozen-thawed ovaries without collagenase pretreatment, even 6 months after transplantation. Thus, the collagenase pretreatment could provide a beneficial approach for maintaining the functions and viability of cryopreserved ovaries in other species and clinically relevant situations.The fertility of young women with malignancies is dramatically decreased by chemical anti-cancer therapies 1,2 . To preserve patient fertility, assisted reproductive technology (ART) is often utilized. When ART is used in infertile women to obtain an increased number of mature oocytes that will enable the best probability of achieving a live birth, controlled ovarian stimulation (COS) is commonly used 3 . However, gonadotropin treatment can lead to the stimulation of non-physiological levels of estrogens that increase the risk of malignant progression in patients with the luminal type of breast cancer 4 . In the case of childhood cancer patients, most ovarian follicles are only at an early stage of development and lack the ability to respond to gonadotropins to reach the ovulatory stage 5 . Therefore, general ART procedures requiring mature oocytes are not adaptable for fertility preservation in young cancer patients. However, cryopreservation of ovarian tissue containing immature oocytes in preantral follicles is an experimental option for patients before the start of chemical anti-cancer therapy 6 .A slow-freezing technique is commonly used for ovarian cryopreservation 7-9 . Ovarian tissues are treated with cryoprotectants such as DMSO, ethylene glycol or sucrose 10 . The ovarian tissues are cooled and then ...

Effects of vitrification solution supplemented with platelet-rich plasma in rat ovarian tissue cryopreservation

“…Ovarian tissue vitrification is known to promote an atretic process in most follicles, except primordial follicles, which are known to better tolerate cryopreservation injury due to their unique structure [ 17 ]. Consistent with past studies [ 18 ], in the current study we also showed that the primordial follicles were mostly well protected in all study groups.…”

Initial response of ovarian tissue transcriptome to vitrification or microwave-assisted dehydration in the domestic cat model

“…For example, dehydration for 10 min led to decrease in the expression of genes enriched in functional terms related to cadherins, cell-cell adhesion factors that play important roles in membrane fusion. Such disturbance in cell-cell adhesion and communication may be a result of exposure to the high osmotic solution during preservation process [ 53 ], and a recent study has shown that the addition of collagen before the exposure to vitrification solution improves viability of secondary follicles in the ovarian tissue [ 54 ].…”

Intercellular communication in the cumulus–oocyte complex during folliculogenesis: A review

“…Fresh follicles were found to have higher levels of CX43 expression than vitrified follicles, and CX43 expression levels were also significantly lower in follicles cultured in vitro for 4 days ( Bus et al, 2021 ), therefore, preservation and promotion of communications in cultured follicles may increase their quality in IVM. Kawai and Shimada found that during vitrification, the attachment of the oocyte to CCs was impaired because of the loss of cadherin adhesion molecules, which was critical for AJs ( Kawai and Shimada, 2020 ). By treating ovaries briefly with collagenase before vitrification, they successfully preserved AJs and maintained the morphology of oocytes, suggesting a new potential approach for raising the functions and viability of cryopreserved ovaries.…”