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Ebrahimi M, Dattena M, Luciano AM, Succu S, Gadau SD, Mara L, Chessa F, Berlinguer F. In vitro culture of sheep early-antral follicles: Milestones, challenges and future perspectives. Theriogenology 2024; 213:114-123. [PMID: 37839290 DOI: 10.1016/j.theriogenology.2023.09.025] [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: 06/03/2023] [Revised: 08/05/2023] [Accepted: 09/29/2023] [Indexed: 10/17/2023]
Abstract
Early antral follicles (EAFs) represent the transitional stage between pre-antral and antral follicles, containing oocytes that have completed most of their growth phase. Therefore, they offer an easily exploitable reserve for producing mature oocytes and preserving genetic resources, given their higher abundance compared to antral follicles (AFs) and shorter culture period than other pre-antral follicles (PAFs). Despite these advantages, the culture of EAFs remains challenging, and the success rates of in vitro embryo production (IVEP) from EAF-derived oocytes are still far below the standard achieved with fully grown oocytes in ruminant species. The difficulty is related to developing suitable in vitro culture systems tailored with nutrients, growth factors, and other signaling molecules to support oocyte growth. In this review, we focus on the in vitro development of sheep EAFs to provide an informative reference to current research progress. We also summarize the basic aspect of folliculogenesis in sheep and the main achievements and limitations of the current methods for EAF isolation, in vitro culture systems, and medium supplementation. Finally, we highlight future perspectives and challenges for improving EAF culture outcomes.
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Affiliation(s)
- Mohammadreza Ebrahimi
- Department of Veterinary Medicine, University of Sassari, Via Vienna 2, Sassari, Italy; Department of Animal Science, Agricultural Research Agency of Sardinia, 07100, Sassari, Italy.
| | - Maria Dattena
- Department of Animal Science, Agricultural Research Agency of Sardinia, 07100, Sassari, Italy
| | - Alberto Maria Luciano
- Reproductive and Developmental Biology Laboratory, Department of Veterinary Medicine and Animal Sciences, University of Milan, Via dell'Università, 6, 26900, Lodi, Italy
| | - Sara Succu
- Department of Veterinary Medicine, University of Sassari, Via Vienna 2, Sassari, Italy
| | - Sergio Domenico Gadau
- Department of Veterinary Medicine, University of Sassari, Via Vienna 2, Sassari, Italy
| | - Laura Mara
- Department of Animal Science, Agricultural Research Agency of Sardinia, 07100, Sassari, Italy
| | - Fabrizio Chessa
- Department of Animal Science, Agricultural Research Agency of Sardinia, 07100, Sassari, Italy
| | - Fiammetta Berlinguer
- Department of Veterinary Medicine, University of Sassari, Via Vienna 2, Sassari, Italy
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Ebrahimi M, Mara L, Chessa B, Chessa F, Parham A, Dattena M. Optimizing injection time of GFP plasmid into sheep zygote. Reprod Domest Anim 2021; 56:467-475. [PMID: 33368650 DOI: 10.1111/rda.13885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 12/14/2020] [Accepted: 12/22/2020] [Indexed: 11/28/2022]
Abstract
Microinjection of exogenous DNA into the cytoplasm of matured oocytes or zygotes is a promising technique to generate transgenic animals. However, the data about the microinjection time and procedure in sheep are limited and have not treated in detail. To obtain more in-depth information, the Sarda sheep oocytes from abattoir-derived ovaries were subjected to IVM and IVF. Then, the GFP plasmid as a reporter gene was injected into the cytoplasm of MII oocytes (n: 95) and zygotes at different post-insemination intervals (6-8 hpi, n: 120; 8-10 hpi, n: 122; 10-12 hpi, n: 110 and 12-14 hpi, n: 96). There were no significant differences in the cleavage rates between the groups. However, blastocyst rate of injected zygotes at all-time intervals was significantly lower than injected MII oocytes and control group (p < 0.05). Interestingly, the proportion of GFP-positive embryos was higher at 8-10 hpi compared with other injected groups (4 % versus 0 %, p < 0.01). Among these, the proportion of mosaic embryos was high and two of those embryos developed to the blastocyst stage. In conclusion, we settled on the cytoplasmic microinjection of GFP plasmid at 8-10 hpi as an optimized time point for the production of transgenic sheep and subsequent experiments.
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Affiliation(s)
- Mohammadreza Ebrahimi
- Department of Basic Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Laura Mara
- Department of Animal Science, Agricultural Research Agency of Sardinia, Sassari, Italy
| | - Bernardo Chessa
- Department of Veterinary Medicine, University of Sassari, Sassari, Italy
| | - Fabrizio Chessa
- Department of Animal Science, Agricultural Research Agency of Sardinia, Sassari, Italy
| | - Abbas Parham
- Department of Basic Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran.,Stem Cell Biology and Regenerative Medicine Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Maria Dattena
- Department of Animal Science, Agricultural Research Agency of Sardinia, Sassari, Italy
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