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ARS Home » Southeast Area » Stoneville, Mississippi » Warmwater Aquaculture Research Unit » Research » Publications at this Location » Publication #375776
Research Project: Biophotonics - The Application of Novel Imaging Methodologies to Livestock Production Research

Location: Warmwater Aquaculture Research Unit

Title: Transition to the ovulatory season in mares: An investigation of antral follicle receptor gene expression in vivo

Author
item ISHAK, GHASSAN - Southern Illinois University
item DUTRA, GABRIEL - Southern Illinois University
item GASTAL, GUSTAVO - Southern Illinois University
item GASTAL, MELBA - Southern Illinois University
item FEUGANG, JEAN - Mississippi State University
item GASTAL, EDUARDO - Southern Illinois University

Submitted to: Molecular Reproduction and Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2019
Publication Date: 9/30/2019
Citation: Ishak, G., Dutra, G., Gastal, G., Gastal, M., Feugang, J., Gastal, E. 2019. Transition to the ovulatory season in mares: An investigation of antral follicle receptor gene expression in vivo. Molecular Reproduction and Development. 86(12):1832-1845.

Interpretive Summary: The inability to obtain in vivo samples of antral follicle wall layers without removing the ovaries or sacrificing the animals has limited more in-depth studies on folliculogenesis, to better understand and improve female fertility. The development of a novel approach of follicular wall biopsy (FWB) and successful utilization on large animals such as mares offer a great combination for future folliculogenesis studies on mechanisms of follicle selection, development, and ovulation in different species.

Technical Abstract: In this study, a novel ultrasound-guided follicle wall biopsy (FWB) technique was used to obtain in vivo follicle wall layers and follicular fluid samples of growing antral follicles. The expression of proliferative, hormonal, angiogenic, and pro-/antiapoptotic receptors and proteins in the follicular wall among three follicle classes were compared during the spring transitional anovulatory (SAN) and spring ovulatory (SOV) seasons in mares. The main findings observed in the granulosa, theca interna, and/or all follicle layers during the SOV season compared with the SAN season were (a) small-sized follicles (10–14 mm) had greater epidermal growth factor receptor (EGFR) and Bcl-2 expression; (b) medium-sized follicles during the expected deviation/selection diameter (20–24 mm) had greater expression of EGFR, Ki-67, luteinizing hormone receptor (LHR), and Bcl-2; and (c) dominant follicles (30–34 mm) had greater EGFR, Ki-67, vascular endothelial growth factor, LHR, and Bcl-2 expression. Estradiol related receptor alpha expression and intrafollicular estradiol concentration increased, along with an increase in follicle diameter in both seasons. In this study, the application of the FWB technique allowed a direct comparison of different receptors’ expression among follicles in different stages of development and between two seasons using the same individuals, without jeopardizing their ovarian function.