Comparison between Slow Freezing and Vitrification in Terms of Ovarian Tissue Viability in a Bovine Model

Abstract

Objective To assess the viability of bovine ovarian tissue after cryopreservation through either slow freezing or vitrification, and to compare it to that of control tissue by performing morphological analyses. Methods The study included 20 bovine ovarian cortex fragments that were divided into control, vitrification, and slow freezing groups. Each group consisted of four fragments of the same ovary, two fixed without cultivation, and two fixed with cultivation. Tissues were evaluated based on follicular morphology immediately after heating and after 7 days of culture, and compared with the control group. Results A total of 240 fragments were analyzed, generating a sample of 1,344 follicles without cultivation and 552 with cultivation. When the non-cultivated samples were classified as non-atretic follicles, 572 were found in the control group, 289 in the vitrification group, and 373 in the slow freezing group, showing no significant differences. When classified as atretic, 46 follicles were found in the control group, 23 in the vitrification group, and 41 in the slow freezing group, also showing no statistical difference. In the post-culture sample, an evolution of the follicular stages could be observed. This finding was important to support that the follicles considered non-atretic in the non-cultivated group were actually viable in the morphological evaluation. Conclusion With no differences between the protocols, vitrification was shown to be an advanced and alternative method for patients who will undergo treatments that

Advances in the Treatment and Prevention of Chemotherapy-Induced Ovarian Toxicity

“…Fourth, the hormonal function of the ovary can be restored, which improves the quality of life for young women. Finally, this technique does not need ovarian stimulation or a sperm donor [ 15 , 88 , 89 , 90 ].…”

Gene banking and transplantation of (mammalian) ovarian tissue

“…Cryopreservation of bovine ovarian tissue was reported in a series of papers from the same Brazilian/Dutch group that had worked on goat and sheep ovaries (Celestino et al, 2008, Santana et al, 2012, Campos et al, 2016. Also other groups have reported on cryopreservation of bovine ovarian tissues e.g.…”

“…(Daniel Jr and Juneja, 1987, Paynter et al, 1999, Isachenko et al, 2002, Lucci et al, 2004, Lamaita et al, 2005, Kagawa et al, 2009, Gerritse et al, 2010, Gerritse et al, 2011, Isachenko et al, 2013, Gao et al, 2016. A number of groups applied vitrification to cryopreserve bovine ovarian tissue (Kagawa et al, 2009, Campos et al, 2016. Cryopreservation after whole ovary perfusion, to load the tissue with cryoprotectants, was reported by three groups (Isachenko et al, 2013, Gao et al, 2016, Westphal et al, 2017.…”

Effects of pentoxifylline on the histological and ultra-structural features of vitrified mouse ovarian tissue: An experimental study

“…The two major techniques for cryopreservation are conventional slow-freezing and vitrification. The main deficiency of slow-freezing is the formation of ice crystal ( 1 ), which leads to serious injury to the tissues and even cell death ( 2 ). Although cryoprotectants can be used to eliminate ice formation, toxicity is the greatest disadvantage of these substances.…”

“…Therefore, the vitrification technique could be used instead to overcome the shortcoming of the slow-freezing technique ( 3 ). In vitrification, transmuting tissue liquid directly into the vitreous solidified status prevents the formation of ice crystals ( 2 , 4 ). The main differences between vitrification and slow-freezing are the rapid cooling and high concentration of subtoxic cryoprotectants ( 5 ).…”