Effects of Cryoprotectant Agents on Equine Ovarian Biopsy Fragments in Preparation for Cryopreservation

Gastal, G. D. A.; Alves, Bênner Geraldo; Alves, Kele Amaral; Paiva, S. O.; Tarso, S. G. S. de; Ishak, G.M.; Bashir, Shah Tauseef; Gastal, E.L.

doi:10.1016/j.jevs.2016.03.014

“…The use of heterotopic autotransplantation and xenotransplantation in livestock may become a powerful tool for (1) treatment of infertility caused by ovarian abnormalities (e.g., benign tumors and adhesions) and oviductal and uterine disorders, and (2) making easier the recovery of immature or mature oocytes from females of high genetic value that need preservation. In the area of preantral follicle research in horses, several studies have been conducted recently on ovarian tissue storage and cryopreservation [12][13][14], in vitro follicle culture [15,16], and preantral follicle population, addressing aspects related to aging effect [17], follicular dynamics [11], and spatial follicle distribution [18].…”

Section: Introductionmentioning

confidence: 99%

Heterotopic autotransplantation of ovarian tissue in a large animal model: Effects of cooling and VEGF

Souza

¹

,

Alves

²

,

Alves

³

et al. 2020

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Heterotopic and orthotopic ovarian tissue autotransplantation techniques, currently used in humans, will become promising alternative methods for fertility preservation in domestic and wild animals. Thus, this study describes for the first time the efficiency of a heterotopic ovarian tissue autotransplantation technique in a large livestock species (i.e., horses) after ovarian fragments were exposed or not to a cooling process (4°C/24 h) and/or VEGF before grafting. Ovarian fragments were collected in vivo via an ultrasound-guided biopsy pick-up method and surgically autografted in a subcutaneous site in both sides of the neck in each mare. The blood flow perfusion at the transplantation site was monitored at days 2, 4, 6, and 7 post-grafting using color-Doppler ultrasonography. Ovarian grafts were recovered 7 days post-transplantation and subjected to histological analyses. The exposure of the ovarian fragments to VEGF before grafting was not beneficial to the quality of the tissue; however, the cooling process of the fragments reduced the acute hyperemia post-grafting. Cooled grafts compared with non-cooled grafts contained similar values for normal and developing preantral follicles, vessel density, and stromal cell apoptosis; lower collagen type III fibers and follicular density; and higher stromal cell density, AgNOR, and collagen type I fibers. In conclusion, VEGF exposure before autotransplantation did not improve the quality of grafted tissues. However, cooling ovarian tissue for at least 24 h before grafting can be beneficial because satisfactory rates of follicle survival and development, stromal cell survival and proliferation, as well as vessel density, were obtained.

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“…Histological studies of the equine ovary have produced limited information regarding the distribution and localization of preantral follicles in the ovarian parenchyma [ 8 – 12 ]. Although several recent studies in mares using ovarian biopsy fragments have advanced our knowledge on preantral follicle population and features [ 13 – 16 ], these reports have not allowed us to determine the spatial distribution of preantral follicles in the whole ovary.…”

Section: Introductionmentioning

confidence: 99%

“…As a result of the lack of information regarding preantral follicle distribution, the ovarian biopsy procedure has been done randomly in several species. This fact has resulted in harvesting of ovarian tissue with an extremely variable number of preantral follicles per fragment (mouse [ 25 ]; woman [ 26 ]; mare [ 16 ]; sheep [ 19 ]; goat [ 27 ]), which can potentially affect the efficiency of assisted reproductive techniques (ARTs), such as cryopreservation and/or transplant. Therefore, comprehensive studies about preantral follicle distribution in the ovary can be helpful for targeting areas with greater numbers of follicles, improving efficiency of the biopsy procedure.…”

Section: Introductionmentioning

confidence: 99%

Spatial distribution of preantral follicles in the equine ovary

Alves

¹

,

Alves

²

,

Gastal

³

et al. 2018

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Comprehensive studies on spatial distribution of preantral follicles in the ovary are scarce. Considering that preantral follicles represent the main ovarian reserve, harvesting of these follicles is crucial for the development/use of assisted reproductive techniques. Therefore, knowledge on follicle spatial distribution can be helpful for targeting areas with richer number of preantral follicles through biopsy procedures. The aim of this study was to assess the distribution and localization of equine preantral follicles according to: (i) age, (ii) ovarian portion (lateral and intermediary) and region (dorsal and ventral), (iii) distance from the geometric center, and (iv) follicular class. Ovaries from young and old mares (n = 8) were harvested in a slaughterhouse and submitted to histological processing for further evaluation. For data analyses, a novel methodology was developed according to the geometric center of each histological section for a precise determination of preantral follicle distribution. Results indicated that (i) equine preantral follicles are clustered and located near to the ovarian geometric center, and that aging induced their dispersion through the ovarian cortex; (ii) the distance from the geometric center was shorter for developing follicles than primordial; and (iii) secondary follicles were more distant from the geometric center but closer to the ovulation fossa. In conclusion, the spatial distribution of preantral follicles was successfully determined in the equine ovary and was affected by age, region, and portion.

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“…Histological studies of the equine ovary have produced limited information regarding the distribution and localization of preantral follicles in the ovarian parenchyma [8][9][10][11][12]. Although several recent studies in mares using ovarian biopsy fragments have advanced our knowledge on preantral follicle population and features [13][14][15][16], these reports have not allowed us to determine the spatial distribution of preantral follicles in the whole ovary.…”

Section: Introductionmentioning

confidence: 99%

Spatial Distribution of Preantral Follicles in the Equine Ovary

Alves

¹

,

Alves

²

,

Gastal

³

et al. 2018

Journal of Equine Veterinary Science

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0

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Comprehensive studies on spatial distribution of preantral follicles in the ovary are scarce. Considering that preantral follicles represent the main ovarian reserve, harvesting of these follicles is crucial for the development/use of assisted reproductive techniques. Therefore, knowledge on follicle spatial distribution can be helpful for targeting areas with richer number of preantral follicles through biopsy procedures. The aim of this study was to assess the distribution and localization of equine preantral follicles according to: (i) age, (ii) ovarian portion (lateral and intermediary) and region (dorsal and ventral), (iii) distance from the geometric center, and (iv) follicular class. Ovaries from young and old mares (n = 8) were harvested in a slaughterhouse and submitted to histological processing for further evaluation. For data analyses, a novel methodology was developed according to the geometric center of each histological section for a precise determination of preantral follicle distribution. Results indicated that (i) equine preantral follicles are clustered and located near to the ovarian geometric center, and that aging induced their dispersion through the ovarian cortex; (ii) the distance from the geometric center was shorter for developing follicles than primordial; and (iii) secondary follicles were more distant from the geometric center but closer to the ovulation fossa. In conclusion, the spatial distribution of preantral follicles was successfully determined in the equine ovary and was affected by age, region, and portion.

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Effects of Cryoprotectant Agents on Equine Ovarian Biopsy Fragments in Preparation for Cryopreservation

Cited by 16 publications

References 57 publications

Heterotopic autotransplantation of ovarian tissue in a large animal model: Effects of cooling and VEGF

Heterotopic autotransplantation of ovarian tissue in a large animal model: Effects of cooling and VEGF

Spatial distribution of preantral follicles in the equine ovary

Spatial Distribution of Preantral Follicles in the Equine Ovary

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