Somatic environment and germinal differentiation in antral follicle: The effect of FSH withdrawal and basal LH on oocyte competence acquisition in cattle

Sirard, Marc‐André

doi:10.1016/j.theriogenology.2016.04.018

Cited by 33 publications

(24 citation statements)

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“…This period of time during folliculogenesis seems important to prepare the granulosa cells for the major change that will occur at ovulation, the modification from an epithelial cell type into a mesenchymal cell type within the future corpus luteum (Khan et al, 2016a). If the basal LH is removed by using GnRH antagonist, a different gene expression condition will emerge (Sirard, 2016) and oocyte quality will decrease rapidly as in atretic follicles . Other experiment testing the quality of oocyte have also confirmed the importance of follicular size to generate blastocysts post fertilization although the effect of early atresia or plateau phase seems more important than size for preparing the oocyte to develop post fertilization (Blondin and Sirard, 1995;Blondin et al, 2002;Nivet et al, 2012).…”

Section: Resultsmentioning

confidence: 99%

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Folliculogenesis and acquisition of oocyte competence in cows

Sirard¹

2019

Anim Reprod

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IVF success depends on hundreds of factors and details but the oocyte quality remains the most important and problematic issue. All antral follicles contain oocytes and all of them have that have reached their full size, can be aspirated, can mature and can be fertilized in vitro. But only a few will make it to embryo unless harvested at a very specific time/status. The conditions impacting the oocyte competence are essentially dependant on the follicular status. Growing follicles contains oocytes that have not completed their preparation, as they are still writing information (RNA), later, dominant follicles or follicles at the plateau phase, stop transcription and become candidates for development. Once in transcriptional arrest, the oocytes, if not ovulated in a short amount of time, do not always make good embryos. This window is affected by time and follicle size and looks like a bell curve. The following review further explain the physiological and molecular evidences that we have to illustrate the competence window and provides clues on how to optimize ovarian stimulation to maximise oocyte quality.

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Section: Resultsmentioning

confidence: 99%

“…Unfortunately, the oocyte competence is not a single instantaneously event but a progressive transformation that occurs in a matter of days in the last part of the follicular wave (Sirard, 2016). The use of ovarian stimulation has been instrumental to learn more about oocyte quality and to obtain more material to study these cells.…”

Section: Introductionmentioning

confidence: 99%

Folliculogenesis and acquisition of oocyte competence in cows

Sirard¹

2019

Anim Reprod

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“…The acquisition of oocyte competence is primarily dependent on the environment of the follicle in which the oocyte resides [44,45] . Indeed, a series of autocrine, paracrine (e.g., GDF9, BMP6 and FGFs) and endocrine (e.g., FSH, LH and estrogen) factors are pivotal in the growth and development of ovarian follicles, and thus impact oogenesis [45][46][47] . These extra and intrafollicular molecules have been demonstrated as crucial components of a signaling network controlling ovarian follicle development [48] .…”

Section: Follicle and Oocyte Qualitymentioning

confidence: 99%

Factors affecting early embryonic development in cattle: relevance for bovine cloning

Dang

Zhang

2019

Front. Agr. Sci. Eng.

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Female infertility represents a major challenge for improving the production efficiency in the dairy industry. Historically, fertility has declined whereas milk yield has increased tremendously due to intensive genetic selection. In vivo evidence reveals about 60% pregnancy loss takes place during the first month following fertilization. Meanwhile, early embryo development is significant for somatic cell nuclear transfer in cattle as a large proportion of cloned embryos fail to develop beyond periimplantation stage. Oocyte quality is of utmost importance for the early embryo to develop to term for both fertilized and cloned embryos. Epigenetic reprogramming is a key process occurring after fertilization and critical roles of epigenetic modifiers during preimplantation development are now clear. Incomplete epigenetic reprogramming is believed to be a major limitation to cloning efficiency. Treatment of cloned embryos with epigenetic modifying drugs (e.g., Trichostatin A) could greatly improve cloning efficiency in both mice and cattle. Recently, the rapid progress in high-throughput sequencing technologies has enabled detailed deciphering of the molecular mechanisms underlying these events. The robust efficiency of genomic editing tools also presents an alternative approach to the functional annotation of genes critical to early development.

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“…The procedure of IVP is best‐developed in cattle. During maturation, the oocyte must undergo a complex array of cytoplasmic rearrangements that allow her to support subsequent fertilization and initiate embryonic development (Sirard, ). Proper maturation of the bovine oocyte from the GV stage to metaphase II takes place within a period of 20–24 hours and is a prerequisite for fertilization and pre‐implantation development.…”

Section: In Vitro Productionmentioning

confidence: 99%

Gene expression analysis and in vitro production procedures for bovine preimplantation embryos: Past highlights, present concepts and future prospects

Wrenzycki

2018

Reprod Domestic Animals

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Contents Over the past decades in vitro production (IVP) of bovine embryos has been significantly improved and in particular bovine IVP is now widely applied under field conditions. This in vitro technique provides new opportunities for cattle producers, particularly in the dairy industry, to overcome infertility and to increase dissemination of animals with high genetic merit. Improvements in OPU/IVP resulted in large‐scale international commercialization. More than half a million IVP embryos are generated on the yearly basis demonstrating the enormous potential of this technology. These advances and the fact that bovine and human early development is remarkably similar have also prompted the use of bovine embryos as a model system to study early mammalian embryogenesis including humans. Despite all the improvements, embryos generated in vitro still differ from their in vivo derived counterparts. Embryos must adjust to multiple microenvironments at preimplantation stages. Consequently, maintaining or mimicking the in vivo situation in vitro will aid to improve the quality and developmental competence of the resulting embryo. The successful clinical application of the techniques in reproductive biotechnology requires both species‐specific clinical skills and extensive laboratory experience. The recent advances in transcriptome profiling have also provided deeper insight into RNA expression and regulation at an unprecedented resolution. The development of these high‐throughput DNA sequencing methods has resulted in new approaches for both mapping and quantifying transcriptomes. The aim of this review is therefore to summarize the available data related to gene expression analyses as well as in vitro embryo production procedures and to provide ideas about future concepts.

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Somatic environment and germinal differentiation in antral follicle: The effect of FSH withdrawal and basal LH on oocyte competence acquisition in cattle

Cited by 33 publications

References 58 publications

Folliculogenesis and acquisition of oocyte competence in cows

Folliculogenesis and acquisition of oocyte competence in cows

Factors affecting early embryonic development in cattle: relevance for bovine cloning

Gene expression analysis and in vitro production procedures for bovine preimplantation embryos: Past highlights, present concepts and future prospects

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