Preantral follicle culture and oocyte quality

Abstract

The formation of high-quality oocytes depends on complex stage-specific interactions between the germ cell and the somatic compartment involving endocrine, paracrine, and autocrine regulation. Cooperativity in bidirectional signalling and metabolism in response to factors in the microenvironment drive growth, proliferation, cell cycle regulation, spindle formation and the establishment of epigenetic marks in oocytes. This is essential to ensure faithful chromosome segregation and to achieve high oocyte quality, with far-reaching consequences for embryo survival, development and the health of offspring. Oocytes reach developmental capacity throughout early meiotic stages up to full growth and acquisition of nuclear and cytoplasmic maturational competence during folliculogenesis. Improved preantral follicle culture in which ideally intimate contacts between oocyte and somatic cells are retained provides unique opportunities to assess the effects of microenvironment, growth factors, hormones, cryopreservation and environmental exposure on folliculogenesis and oocyte quality. An optimised follicle culture can contribute to the generation of high-quality oocytes for use in fertility preservation in cancer patients, animal breeding and the preservation of endangered species. The past decade has brought about major advances in follicle culture from different species. Recent advances in preantral follicle culture are discussed to assess the effects of environment, adverse exposure, cryopreservation and age on oocyte quality.

In vitro culture of mechanically isolated murine primary follicles in the presence of human platelet lysate PLTMax

“…This method has an advantage over the two-dimensional culture system, as it prevents cell adhesion to the culture dish's surface while preserving the follicle's three-dimensional structure (Nikiforov et al, 2018). This mode also ensures the homogeneous delivery of nutrients to the follicle, promotes the maintenance of intercellular junctions, and helps maintain the oocyte within the granulosa cell layers (Asaduzzman et al, 2018;Heiligentag & Eichenlaub-Ritter, 2017). However, three-dimensional cultures using a gel matrix have limitations in providing nutrients to the developing tissue mass, as the substance in which the follicle is encapsulated exerts an inhibitory control on follicular growth initiation (Shea et al, 2014).…”

Human ovarian follicular granulosa cells isolated during ART procedure reflect substantial changes in activation of hormonal signaling pathways, during long-term in vitro conditions

“…The names of the GOs were presented as abbreviations: CBP -cholesterol biosynthetic process (GO:0006695); RoLBP-regulation of lipid biosynthetic process (GO:0046890); RoLMP -regulation of lipid metabolic process (GO:0019216); RTI -response to insulin (GO:0032868); RTL response to lipopolysaccharide (GO:0032496). The genes participating only in one GO were excluded from the figure more steroid levels in follicular fluid may be useful to predict suitability of an oocyte for IVF [14,15]. GCs fulfil many roles.…”

Effect of Ethylene Glycol on Structural Integrity at Each Stage of Preantral Follicle Development Post Vitrification of Rat Ovary-Histological Analysis

“…Secondary follicles have a stratification of the granulosa cell layer and differentiation of this layer into a special layer, theca cells, that have an affinity for local growth factors and gonadotropins. Therefore, these structures are thought to strengthen the resistance of secondary follicles to post-vitrification cryoinjury (Heiligentag and Eichenlaub-Ritter 2018).…”