• Oocytes were collected from slaughterhouse-derived ovaries, matured in vitro, and injected with frozen-thawed stallion sperm. (bioone.org)
  • These protease-induced decreases in IGFBP-4 and -5 likely cause increased levels of bioavailable (or free) IGFs that stimulate steroidogenesis and mitogenesis in developing dominant follicles, which ultimately prepare the follicle(s) and oocyte(s) for successful ovulation and fertilization. (bioone.org)
  • The present review discusses methods to improve oocyte quality in older women and new stimulation protocols that may improve the number of mature oocytes retrieved during an in vitro fertilization cycle. (arvigen.com)
  • Increased IGFBP-4 and -5 protease along with lower amounts of IGFBP-4 binding activity and greater amounts of free IGF-I are some of the earliest developmental changes documented in bovine growing antral follicles. (bioone.org)
  • As a result, these aged mice had more oocytes with stimulation, the developmental potential of the oocytes was improved, and more offspring were born compared to old animals receiving placebo 1. (arvigen.com)
  • In vivo development was assessed after transfer of injected oocytes to the oviducts of recipient mares. (bioone.org)
  • In some species (e.g., bovine), evidence indicates that decreases in IGFBP-4 and -5 levels in estrogen-dominant preovulatory follicles are likely due, in part, to increased protease activity, whereas lower levels of IGFBP-2 are not due to increased proteolysis. (bioone.org)
  • in 2015 showed that supplementation of CoQ10 in an aged animal model delayed decline in ovarian reserve, restored oocyte mitochondrial gene expression, and improved mitochondrial activity with a significant reduction in oocyte aneuploidy. (arvigen.com)
  • Human oocyte maturation arrest represents one of the severe conditions for female patients with primary infertility. (bvsalud.org)
  • Together, our studies identified and characterized novel biallelic variants in MAD2L1BP responsible for human oocyte maturation arrest at MI, and thus prompted new therapeutic avenues for curing female primary infertility. (bvsalud.org)
  • The released oocyte is surrounded by a thick specialised extracellular matrix, the zona pellucida , that in turn is covered in layers of cells, the granulosa layer . (edu.au)
  • 8 ) suggested a simple method for selection of porcine oocytes based on the enzymatic activity of glucose-6-phosphate dehydrogenase (G6PDH), a component of the pentose cycle synthesized during the oogenesis. (macvetrev.mk)
  • Complete in vitro oogenesis: retrospects and prospects [3] "In reality the vast majority of oocytes formed from primordial germ cells (PGCs) will undergo apoptosis, or other forms of cell death. (edu.au)
  • However, to recapitulate mammalian oogenesis and produce fertilizable oocytes in vitro is a complex process involving several different cell types, precise follicular cell-oocyte reciprocal interactions, a variety of nutrients and combinations of cytokines, and precise growth factors and hormones depending on the developmental stage. (edu.au)
  • The primary objective of the present study of women participating in an ICSI program was to determine whether the morphologic quality of oocytes was related to the polycystic ovary syndrome (PCOS) phenotype. (biomedcentral.com)
  • The oocyte (eggs, ova, ovum) is arrested at an early stage of the first {{meiosis))(first meiotic) division as a primary oocyte (primordial follicle) within the ovary . (edu.au)
  • A total of 1496 metaphase II oocytes ( n = 602 for phenotype A combining PCOM + HA + OA, n = 462 oocytes for phenotype C: PCOM + HA, and n = 432 for phenotype D: PCOM + OA) were assessed. (biomedcentral.com)
  • Early oocytes are also classified as immature (germinal vesicle (GV) or metaphase I (MI) stage). (edu.au)
  • In this study, by whole-exome sequencing (WES), we identified homozygous and compound heterozygous MAD2L1BP variants in three families with female patients diagnosed with primary infertility owing to oocyte metaphase I (MI) arrest. (bvsalud.org)
  • Oocyte quality and maturity are the most important determinants of blastocyst developmental competence ( 3 ). (macvetrev.mk)
  • Therefore, MTOR-dependent pathways in primordial or growing oocytes differentially affected downstream processes including follicular development, sex-specific identity of early granulosa cells, maintenance of oocyte genome integrity, oocyte gene expression, meiosis, and preimplantation developmental competence. (edu.au)
  • In the first part of the study, cumulus-oocytes complexes (COCs) (n=434) were aspirated from 60 ovaries. (macvetrev.mk)
  • These findings showed that COCs with high morphological characteristics had higher developmental ability compared to COCs with low morphology. (macvetrev.mk)
  • In the reproductive system, despite Gsα being associated with oocyte meiotic arrest in vitro, the exact role of Gsα in female fertility in vivo remains largely unknown. (edu.au)
  • Although poor oocyte quality accounts for most female fertility problems, little is known about how oocytes maintain cellular fitness, or why their quality eventually declines with age2. (bvsalud.org)
  • meiosis in Gsα-deficient oocytes precociously resumed in only 43% of antral follicles from mutant mice, indicating that alteration of meiotic pause was not the key factor in infertility. (edu.au)
  • Here we show that conditional knockout (cKO) of Mtor in either primordial or growing oocytes caused infertility but differentially affected oocyte quality, granulosa cell fate, and follicular development. (edu.au)
  • Likewise, there were no significant intergroup differences in oocyte morphology. (biomedcentral.com)
  • The goal of this study was to use a physiologic aging mouse model, in which egg aneuploidy levels increase, to determine whether there are age-dependent differences in morphokinetic parameters of oocyte maturation. (bvsalud.org)
  • There were no differences in the morphokinetic parameters of oocyte maturation between oocytes from reproductively young and old mice with respect to time to germinal vesicle breakdown (GVBD) (1.03 ± 0.03 vs. 1.01 ± 0.04 h), polar body extrusion (PBE) (8.56 ± 0.11 vs. 8.52 ± 0.15 h), duration of meiosis I (7.58 ± 0.10 vs. 7.48 ± 0.11 h), and kinetics of cumulus expansion (0.093 ± 0.002 vs. 0.089 ± 0.003 µm/min). (bvsalud.org)
  • The BCB-staining in high-quality oocytes did not have a significant impact on their maturation ability compared to a control group, but it might be useful for selecting developmentally competent oocytes with low morphology characteristics. (macvetrev.mk)
  • It is believed that one of the causes is an early stage of degeneration of oocytes with normal morphology ( 7 ). (macvetrev.mk)
  • The phenotypes A, C and D did not differ significantly with regard to the proportion of normal oocytes (adjusted percentages (95%CI): 35.2% (31.5 to 39.1%), 25.8% (21.9 to 29.9%) and 34.0% (29.7 to 38.6%), respectively: adjusted p = 0.13). (biomedcentral.com)
  • The present study is the first to show that the PCOS phenotype (notably the presence vs. absence of OA and/or HA) is not significantly associated with the morphological quality of oocytes. (biomedcentral.com)
  • Furthermore, the level of ROS (reactive oxygen species) and the mitochondrial aggregation increased, and antioxidant glutathione (GSH) content, ATP level, mtDNA copy number, and mitochondrial membrane potential decreased in Gsα-deficient oocytes. (edu.au)
  • Yet, how healthy oocytes balance essential mitochondrial activity with the production of ROS is unknown. (bvsalud.org)
  • Here we show that oocytes evade ROS by remodelling the mitochondrial electron transport chain through elimination of complex I. Combining live-cell imaging and proteomics in human and Xenopus oocytes, we find that early oocytes exhibit greatly reduced levels of complex I. This is accompanied by a highly active mitochondrial unfolded protein response, which is indicative of an imbalanced electron transport chain. (bvsalud.org)
  • The breakdown of the germinal vesicle indicates a resumption of meiosis and the extrusion of the first polar body (1 PB) indicates completion of the first meiotic division in human oocytes. (edu.au)
  • Oocyte-specific deletion of Gsα induces oxidative stress and deteriorates oocyte quality in mice [1] "The stimulatory heterotrimeric Gs protein alpha subunit (Gsα) is a ubiquitous guanine nucleotide-binding protein that regulates the intracellular cAMP signaling pathway and consequently participates in a wide range of biological events. (edu.au)
  • Here, we generated oocyte-specific Gsα knockout mice by using the Cre/LoxP system. (edu.au)
  • GV oocytes from mutant mice showed early-stage apoptosis. (edu.au)
  • Oocyte stage-specific effects of MTOR determine granulosa cell fate and oocyte quality in mice [2] "MTOR (mechanistic target of rapamycin) is a widely recognized integrator of signals and pathways key for cellular metabolism, proliferation, and differentiation. (edu.au)
  • RESULTS: Oocytes from reproductively old mice were smaller than young counterparts in terms of GV area (446.42 ± 4.15 vs. 416.79 ± 5.24 µm2, p (bvsalud.org)
  • cRNA microinjection of full-length or truncated MAD2L1BP uncovered their discordant roles in driving the extrusion of polar body 1 (PB1) in mouse oocytes. (bvsalud.org)
  • Furthermore, the patient's oocytes carrying the mutated MAD2L1BP resumed polar body extrusion (PBE) when rescued by microinjection of full-length MAD2L1BP cRNAs. (bvsalud.org)
  • The selection of oocytes with high quality is not important only for in vitro production (IVP), but also for other procedures such as pronuclear microinjections, intracytoplasmic sperm injection and nuclear transplantation ( 4 ). (macvetrev.mk)
  • The primary criterion widely used for oocyte quality assessment is morphological classification. (macvetrev.mk)
  • Nevertheless, it is likely that the oocytes are of poor morphologic quality in cases of full-blown PCOS. (biomedcentral.com)
  • Meanwhile, the Gsα knockout-induced decline in oocyte quality and low developmental potential was partially rescued by antioxidant supplementation. (edu.au)
  • The aim of the current study was to assess the relationship between BCB staining in porcine oocytes with high and low morphological characteristics and its maturation rate. (macvetrev.mk)
  • reported in vitro procedures that appear to reproduce efficiently these conditions allowing for the production, completely in a dish, of a relatively large number of oocytes that are fertilizable and capable of giving rise to viable offspring in the mouse. (edu.au)
  • CONCLUSION: There is no association between age or ploidy and the morphokinetics of mouse oocyte in vitro maturation (IVM). (bvsalud.org)
  • A way to solve this limitation could be to produce large numbers of oocytes, in vitro, from stem cells. (edu.au)
  • It has been established that G6PDH gets inactivated as soon as the oocytes complete their growth ( 4 ). (macvetrev.mk)
  • The assisted reproduction techniques in animal species remain an important and essential tool for safe and efficient breeding, as well as for the improvement of the genetic value of domestic animals ( 1 ). (macvetrev.mk)
  • Due to the high enzymatic activity of G6PDH in growing oocytes, the BCB stain is metabolized, the oocytes remain unstained, and are categorized as BCB-negative (BCB-) ( 10 ). (macvetrev.mk)
  • Oocytes form before birth and remain viable for several decades before fertilization1. (bvsalud.org)
  • However, some studies in cattle and other species show that the morphological classification is insufficient because up to 60% of the IVM/IVF oocytes fail to reach the blastocyst stage ( 4 ). (macvetrev.mk)
  • Oocytes used for in vitro production are most frequently retrieved from ovaries obtained from slaughterhouses. (macvetrev.mk)