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Borges MA, Curcio BR, Gastal GDA, Gheno L, Junior ASV, Corcini CD, Nogueira CEW, Aguiar FLN, Gastal EL. Ethanol, Carnoy, and paraformaldehyde as fixative solutions for histological evaluation of preantral follicles in equine ovarian tissue. Reprod Biol 2023; 23:100814. [PMID: 37890396 DOI: 10.1016/j.repbio.2023.100814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 09/24/2023] [Accepted: 09/27/2023] [Indexed: 10/29/2023]
Abstract
The most adequate fixative solution for equine ovarian tissue is still to be determined as a tool to evaluate the improvement of methodological studies in assisted reproductive techniques and fertility preservation. This study aimed to evaluate a short-time ethanol 70% (ST-EtOH, 45 min) exposure as an alternative fixative compared with two classically fixatives [Carnoy's (CAR) solution and paraformaldehyde 4% (PFA)] at different fixation times (6 h, 12 h). The end points evaluated were morphology and classes of preantral follicles, follicular and stromal cell densities, and follicular and oocyte nuclear diameters in equine ovarian tissue. Ovaries (n = 6) from ovariectomized young mares were fragmented (3 × 3 × 1 mm; 20 fragments/ovary) and fixed in the tested treatments. Overall, a total of 11,661 preantral follicles were evaluated in 1444 histological slides. The ST-EtOH similarly preserved the preantral follicle morphometry and stromal cell density compared to the PFA fixative, regardless of the exposure time. Nonetheless, the CAR fixative solution had the greatest percentage of normal preantral follicles and the highest stromal cell density among all treatments. In conclusion, Carnoy's solution must be preferred compared with ST-EtOH and PFA fixatives for studies concerning the cellular morphology of equine ovarian tissue. Moreover, ST-EtOH fixative is a good alternative for equine ovarian tissue when a quick histological evaluation is required instead of more time-consuming and expensive techniques. Additional studies concerning the impact of different fixatives on the ultrastructure of cellular populations and their compatibility with IHC and molecular techniques in equine ovarian tissue are warranted.
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Affiliation(s)
- Morgana A Borges
- Department of Veterinary Clinics, College of Veterinary Medicine, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Bruna R Curcio
- Department of Veterinary Clinics, College of Veterinary Medicine, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Gustavo D A Gastal
- Instituto Nacional de Investigación Agropecuaria, Estación Experimental INIA La Estanzuela, Colonia, Uruguay
| | - Luiza Gheno
- Department of Veterinary Clinics, College of Veterinary Medicine, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Antonio S Varela Junior
- Department of Comparative Animal Reproduction, Institute of Biological Sciences, Federal University of Rio Grande, Rio Grande, RS, Brazil
| | - Carine D Corcini
- Department of Veterinary Clinics, College of Veterinary Medicine, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Carlos E W Nogueira
- Department of Veterinary Clinics, College of Veterinary Medicine, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Francisco L N Aguiar
- Department of Veterinary Medicine, Sousa Campus, Federal Institute of Education, Science and Technology of Paraiba, Sousa, PB, Brazil
| | - Eduardo L Gastal
- Animal Science, School of Agricultural Sciences, Southern Illinois University, Carbondale, IL, USA.
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Spatial distribution of preantral follicles in ovarian parenchyma of bovine species. ZYGOTE 2023; 31:195-200. [PMID: 36793125 DOI: 10.1017/s0967199423000023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The goal of this study was to determine the distribution of preantral follicles in bovine ovaries. Follicular distribution in the ovaries (n = 12) was evaluated in the region of the greater curvature of the ovary (GCO) and the region close to the ovarian pedicle (OP) of Bos taurus indicus heifers of the Nelore breed. Two fragments were obtained from each region of the ovary (GCO and OP). The mean weight of the ovaries was 4.04 ± 0.32 g. The mean antral follicle count (AFC) was 54.58 ± 3.55 follicles (minimum and maximum variation of 30 and 71 follicles, respectively). In total, 1123 follicles were visualized in the region of the GCO; 949 (84.5%) of them were primordial follicles and 174 (15.5%) were developing follicles. The region close to the OP contained 1454 follicles, of which 1266 (87%) were primordial follicles and 44 (12.9%) were developing follicles. The OP region showed a higher proportion of intact follicles in the primordial (P < 0.0001) and primary (P = 0.042) stages compared with the GCO region. The proportion of secondary follicles was similar in the OP and GCO regions. The ovaries of two bovine females (16%; 2/12) contained multi-oocytes follicles, which were characterized as primary follicles. Therefore, the distribution of preantral follicles in the bovine ovary was heterogeneous, with the region close to the OP containing a greater number of preantral follicles compared with the GCO region (P < 0.05).
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Harvesting, processing, and evaluation of in vitro-manipulated equine preantral follicles: A review. Theriogenology 2020; 156:283-295. [PMID: 32905900 DOI: 10.1016/j.theriogenology.2020.06.044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 06/27/2020] [Indexed: 12/14/2022]
Abstract
The mammalian ovary is responsible for essential stages of folliculogenesis and hormonal production, regulating the female physiological functions during the menstrual/estrous cycles. The mare has been considered an attractive model for comparative studies due to the striking similarities shared with women regarding in vivo and in vitro folliculogenesis. The ovarian follicular population in horses contains a large number of oocytes enclosed in preantral follicles that are yet to be explored. Therefore, the in vitro manipulation of equine preantral follicles aims to avoid the process of atresia and promote the development of follicles with competent oocytes. In this regard, after ovarian tissue harvesting, the use of appropriate processing techniques, as well as suitable approaches to evaluating equine preantral follicles and ovarian tissue, are necessary. Although high-quality equine ovarian tissue can be obtained from several sources, some critical aspects, such as the age of the animals, ovarian cyclicity, reproductive phase, and the types of ovarian structures, should be considered. Therefore, this review will focus on providing an update on the most current advances concerning the critical factors able to influence equine preantral follicle quality and quantity. Also, the in vivo strategies used to harvest equine ovarian tissue, the approaches to manipulating ovarian tissue post-harvesting, the techniques for processing ovarian tissue, and the classical approaches used to evaluate preantral follicles will be discussed.
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Aguiar FLN, Gastal GDA, Alves KA, Alves BG, Figueiredo JR, Gastal EL. Supportive techniques to investigate in vitro culture and cryopreservation efficiencies of equine ovarian tissue: A review. Theriogenology 2020; 156:296-309. [PMID: 32891985 DOI: 10.1016/j.theriogenology.2020.06.043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 06/27/2020] [Indexed: 12/22/2022]
Abstract
During the reproductive lifespan of a female, only a limited quantity of oocytes are naturally ovulated; therefore, the mammalian ovary possesses a substantial population of preantral follicles available to be handled and explored in vitro. Hence, the manipulation of preantral follicles enclosed in ovarian tissue aims to recover a considerable population of oocytes of high-value animals for potential application in profitable assisted reproductive technologies (ARTs). For this purpose, the technique of preantral follicle in vitro culture (IVC) has been the most common research tool, achieving extraordinary results with offspring production in the mouse model. Although promising outcomes have been generated in livestock animals after IVC of preantral follicles, the quantity and quality of embryo production with those oocytes are still poor. In recent years, the mare has become an additional model for IVC studies due to remarkable similarities with women and livestock animals regarding in vivo and in vitro ovarian folliculogenesis. For a successful IVC system, several factors should be carefully considered to provide an optimum culture environment able to support the viability and growth of preantral follicles enclosed in ovarian tissue. The cryopreservation of the ovarian tissue is another important in vitro manipulation technique that has been used to preserve the reproductive potential in humans and, in the future, may be used in highly valuable domestic animals or endangered species. Several improvements in cryopreservation protocols are necessary to support the utilization of ovarian tissue of different species in follow-up ARTs (e.g., ovarian fragment transplantation). This review aims to provide an update on the most current advances regarding supportive in vitro techniques used in equids to evaluate and manipulate preantral follicles and ovarian tissue, as well as methodological approaches used during IVC and cryopreservation techniques.
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Affiliation(s)
- F L N Aguiar
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, IL, USA; Laboratory of Manipulation of Oocytes and Preantral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, State University of Ceará, Fortaleza, Ceará, Brazil; Department of Veterinary Medicine, Sousa Campus, Federal Institute of Education, Science and Technology of Paraíba, Sousa, Paraíba, Brazil.
| | - G D A Gastal
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, IL, USA; National Institute of Agricultural Research, INIA La Estanzuela, Colonia, Uruguay
| | - K A Alves
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, IL, USA; Laboratory of Manipulation of Oocytes and Preantral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, State University of Ceará, Fortaleza, Ceará, Brazil; Postgraduate Program of Gynecology and Obstetrics, Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - B G Alves
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, IL, USA; Laboratory of Manipulation of Oocytes and Preantral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, State University of Ceará, Fortaleza, Ceará, Brazil; Animal Bioscience Postgraduate Program, Federal University of Goiás, Jataí, Goiás, Brazil
| | - J R Figueiredo
- Laboratory of Manipulation of Oocytes and Preantral Follicles (LAMOFOPA), Faculty of Veterinary Medicine, State University of Ceará, Fortaleza, Ceará, Brazil
| | - E L Gastal
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, IL, USA.
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Max MC, Bizarro-Silva C, Búfalo I, González SM, Lindquist AG, Gomes RG, Barreiros TRR, Lisboa LA, Morotti F, Seneda MM. In vitro culture supplementation of EGF for improving the survival of equine preantral follicles. In Vitro Cell Dev Biol Anim 2018; 54:687-691. [PMID: 30284096 DOI: 10.1007/s11626-018-0296-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 09/19/2018] [Indexed: 11/30/2022]
Abstract
Folliculogenesis is a process of development and maturation of the ovarian follicles, being essential for the maintenance of fertility. In in vivo conditions, 99.9% of the follicles of an ovary do not ovulate and undergo atresia. In order to minimize this loss and to clarify the existing mechanisms, a technique was developed that allows for the in vitro follicular development. The objective of this study was to evaluate the effects of different epidermal growth factor (EGF) concentrations on the in vitro culturing of equine preantral follicles. Ovaries (n = 10) were collected from a local slaughterhouse of mares in seasonal anestrus, washed with 70% alcohol and PBS, and transported. The inner portion of the ovary was divided into 11 fragments of approximately 3 × 3 × 1 mm. A fragment of each ovary was immediately fixed in Bouin (control group). The remaining 10 fragments were individually cultured for 2 and 6 d. The medium was supplemented with different concentrations of EGF (0, 10, 50, 100, and 200 ng/mL). After cultivation, the fragments were processed and classified according to the developmental stage and morphology. In total, 1065 slides containing 6105 tissue sections were evaluated. Within 2 d of culture, there was a higher proportion of intact follicles at the EGF concentrations of 0 and 100 ng/mL (p > 0.05). After 6 d of culture, only the EGF concentration of 100 ng/mL demonstrated a difference when compared to the other treatments (0, 10, 50 and 200 ng/mL of EGF, p > 0.05). There was follicular development after 2 d at all EGF concentrations. Thus, we suggest that EGF promotes follicular survival in equines at a concentration of 100 ng/mL in in vitro cultures of ovarian fragments for 2 d. In addition, we suggest that EGF promotes follicular survival in equines at a concentration of 100 ng/mL in situ cultivation.
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Affiliation(s)
- Marilu Constantino Max
- Department of Veterinary Clinical, Laboratory of Animal Reproduction, University of Londrina, Londrina, Parana, Brazil
| | - Camila Bizarro-Silva
- Department of Veterinary Clinical, Laboratory of Animal Reproduction, University of Londrina, Londrina, Parana, Brazil. .,Laboratory Animal Reproduction, DCV, CCA, UEL, Londrina, PR, 86051-990, Cx. Postal: 10.011, Brazil.
| | - Isabela Búfalo
- Department of Veterinary Clinical, Laboratory of Animal Reproduction, University of Londrina, Londrina, Parana, Brazil
| | - Suellen Miguez González
- Department of Veterinary Clinical, Laboratory of Animal Reproduction, University of Londrina, Londrina, Parana, Brazil
| | - Andressa Guidugli Lindquist
- Department of Veterinary Clinical, Laboratory of Animal Reproduction, University of Londrina, Londrina, Parana, Brazil
| | - Roberta Garbelini Gomes
- Department of Veterinary Clinical, Laboratory of Animal Reproduction, University of Londrina, Londrina, Parana, Brazil
| | - Thales Ricardo Rigo Barreiros
- Department of Veterinary and Animal Production, Laboratory of Biotechnology of Animal Reproduction, State University of Northern Parana, Jacarezinho, Parana, Brazil
| | - Lívia Aires Lisboa
- Department of Veterinary Clinical, Laboratory of Animal Reproduction, University of Londrina, Londrina, Parana, Brazil
| | - Fábio Morotti
- Department of Veterinary Clinical, Laboratory of Animal Reproduction, University of Londrina, Londrina, Parana, Brazil
| | - Marcelo Marcondes Seneda
- Department of Veterinary Clinical, Laboratory of Animal Reproduction, University of Londrina, Londrina, Parana, Brazil
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Alves BG, Alves KA, Gastal GDA, Gastal MO, Figueiredo JR, Gastal EL. Spatial distribution of preantral follicles in the equine ovary. PLoS One 2018; 13:e0198108. [PMID: 29897931 PMCID: PMC5999074 DOI: 10.1371/journal.pone.0198108] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/14/2018] [Indexed: 11/19/2022] Open
Abstract
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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Affiliation(s)
- Benner G. Alves
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, Illinois, United States of America
| | - Kele A. Alves
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, Illinois, United States of America
| | - Gustavo D. A. Gastal
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, Illinois, United States of America
| | - Melba O. Gastal
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, Illinois, United States of America
| | - José R. Figueiredo
- Laboratory of Manipulation of Oocytes and Preantral Follicles (LAMOFOPA), State University of Ceará, Fortaleza, CE, Brazil
| | - Eduardo L. Gastal
- Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, Illinois, United States of America
- * E-mail:
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