The fate of thecal smooth muscle cells in postovulatory hamster follicles

Martin, Gary G.; Steenwyk, Gretchen van; Miller‐Walker, Cindy

doi:10.1002/ar.1092070205

Cited by 10 publications

(1 citation statement)

References 44 publications

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“…Two DEGs serve other roles in cumulus cells ( FGG , MDFI ). FGG has a role in regulation of blood clotting ( Simurda et al , 2020 ) and MDFI inhibits myogenesis ( Berkes and Tapscott, 2005 ) and may have a role in ovulation ( Espey, 1978 ; Martin et al , 1983 ). Thus, dysregulation of FGG and MDFI could contribute to the reduced ovulation rate observed for the heifers subjected to Ex-cpFSH during ovarian stimulation in our previous study ( Karl et al , 2021 ).…”

Section: Discussionmentioning

confidence: 99%

Ovarian stimulation with excessive FSH doses causes cumulus cell and oocyte dysfunction in small ovarian reserve heifers

Karl,

Schall,

Clark

et al. 2023

Molecular Human Reproduction

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Excessive FSH doses during ovarian stimulation in the small ovarian reserve heifer (SORH) cause premature cumulus expansion and follicular hyperstimulation dysgenesis (FHD) in nearly all ovulatory-size follicles with predicted disruptions in cell-signaling pathways in cumulus cells and oocytes (before ovulatory hCG stimulation). These observations support the hypothesis that excessive FSH dysregulates cumulus cell function and oocyte maturation. To test this hypothesis, we determined whether excessive FSH-induced differentially expressed genes (DEGs) in cumulus cells identified in our previously published transcriptome analysis were altered independent of extreme phenotypic differences observed amongst ovulatory-size follicles, and assessed predicted roles of these DEGs in cumulus and oocyte biology. We also determined if excessive FSH alters cumulus cell morphology, and oocyte nuclear maturation before (premature) or after an ovulatory hCG stimulus or during IVM. Excessive FSH doses increased expression of 17 cumulus DEGs with known roles in cumulus cell and oocyte functions (responsiveness to gonadotrophins, survival, expansion, and oocyte maturation). Excessive FSH also induced premature cumulus expansion and oocyte maturation but inhibited cumulus expansion and oocyte maturation post-hCG and diminished the ability of oocytes with prematurely expanded cumulus cells to undergo IVF or nuclear maturation during IVM. Ovarian stimulation with excessive FSH is concluded to disrupt cumulus cell and oocyte functions by inducing premature cumulus expansion and dysregulating oocyte maturation without an ovulatory hCG stimulus yielding poor-quality cumulus-oocyte complexes that may be incorrectly judged morphologically as suitable for IVF during ART.

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Section: Discussionmentioning

confidence: 99%

Ovarian stimulation with excessive FSH doses causes cumulus cell and oocyte dysfunction in small ovarian reserve heifers

Karl,

Schall,

Clark

et al. 2023

Molecular Human Reproduction

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Ovulation in the animal kingdom: A review with an emphasis on the role of contractile processes

Schroeder

Talbot

1985

Gamete Research

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INTRODUCTIONIn most sexually reproducing animals, oocytes develop within an organized tissue sac, the follicle; oocytes and follicle cells are assembled together in the unovulated follicle, which is solid in all but therian mammals. Before fertilization, the oocyte generally abandons the follicle and moves to another site for subsequent spawning or further development. The process of escape from the follicle is termed ovulation; we shall also use this term to refer to the escape of the oocyte from its surrounding tissue in those metazoans that lack an organized follicle. In general, ovulation is at least a two-part phenomenon involving enzymatic degradation and rupture of the follicle followed by the actual movement of the oocyte out of the follicle. These steps were proposed by Schochet [1916] for mammalian ovulation, and by Rugh El9351 for frogs, and seem to be generally applicable to those phyla in which no intrafollicular antral space is present at the time of ovulation.We have reviewed information on the mechanism of oocyte extrusion in animals throughout the phylogenetic series, paying particular attention to the role of contractility in the process. Contraction of a follicle implies the presence of contractile cells in or around the follicle. A variety of contractile systems has been described in follicles from diverse animal types, and we feel it is now worthwhile to review the question of contractile mechanisms in ovulation from an evolutionary point of view. For each group we discuss, we will examine, to the extent information is available, 1) evidence that contractile cells are present near the developing oocyte, 2) experimental evidence that contractile cells are involved in ovulation, and 3) factors that may regulate contraction of these cells. It will become apparent that information on the mechanics of ovulation in other than eutherian mammals is scarce. Current information makes it clear that cells that are contractile or potentially capable of

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