• Oocytes were collected from aspirated porcine tertiary follicles. (biomedcentral.com)
  • 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)
  • ATZ also induces morphological changes similar to apoptosis and initiates mitochondria-dependent cell death in several experimental models. (frontiersin.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)
  • As a follow-up study, conditional disruption of the gene PDSS-2, resulting in isolated CoQ deficiency in the oocytes of young animals, resulted in phenotypic changes characteristic of oocyte mitochondrial dysfunction associated with aging. (arvigen.com)
  • The mammalian genome comprises nuclear DNA (nDNA) derived from both parents and mitochondrial DNA (mtDNA) that is maternally inherited and encodes essential proteins required for oxidative phosphorylation. (regenerativemedicine.net)
  • Germinal vesicle breakdown (GVBD) occurs during oocyte meiotic maturation, a period when transcriptional processes are virtually inactive. (biomedcentral.com)
  • Inhibition of nuclear meiotic maturation via IBMX significantly increased MIR21 and decreased its target, PDCD4. (biomedcentral.com)
  • Our results indicate MIR21 is active and important during meiotic maturation of the oocyte. (biomedcentral.com)
  • The oocyte must maintain arrest at the diplotene stage until meiotic resumption occurs. (biomedcentral.com)
  • Of particular interest is understanding the role of non-coding RNA in regulating meiotic checkpoints in the oocyte, particularly that of microRNA-21 (MIR21). (biomedcentral.com)
  • The decreased quality of oocytes involves an increased rate of chromosomal aneuploidy with aging predominantly related to meiotic errors during oocyte maturation. (arvigen.com)
  • The aim of this study was to assess the effects of brief, intense exposure to tobacco smoke on granulosa cell number, oocyte growth, and follicle size during puberty in female Swiss mice. (biomedcentral.com)
  • Following germinal vesicle break down (GVBD) the oocyte is transcriptionally quiescent until fertilization and activation of the embryonic genome, occurring at the four-cell stage of development in the pig [ 9 ]. (biomedcentral.com)
  • 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)
  • Recurrent implantation failure (RIF) refers to cases in which women have had three failed in vitro fertilization (IVF) attempts with good quality embryos. (biomedcentral.com)
  • Although there is no accepted formal definition for recurrent implantation failure, Orvieto suggests that it is after three failed in vitro fertilization-embryo transfer (IVF-ET) cycles with good quality embryos transferred [ 5 ]. (biomedcentral.com)
  • Maturation of the mammalian oocyte is a complex process involving internal checkpoints and bidirectional communication with the surrounding cumulus cells. (biomedcentral.com)
  • This study was conducted to evaluate in vivo and in vitro development of in vitro-matured equine oocytes fertilized by intracytoplasmic sperm injection. (bioone.org)
  • In vivo development was assessed after transfer of injected oocytes to the oviducts of recipient mares. (bioone.org)
  • This review focuses on the differential responses of cell types to ATZ toxicity, testicular effects of ATZ in both in vitro and in vivo models and chemopreventive strategies, so as to highlight the current state of the art on the toxicological outcomes of ATZ exposure in several experimental model systems. (frontiersin.org)
  • In the initial segment of the epididymis, the sperm cell is immotile-unable to fertilize an oocyte and has a proximal cytoplasmic droplet-close to the neck [ 3 ] . (encyclopedia.pub)
  • Thus, the maturing oocyte is reliant on processes such as post-transcriptional gene regulation (PTGR) to regulate the mRNA and protein repertoire. (biomedcentral.com)
  • The inability to transcribe mRNA during this stage of development and the probable necessity for post-transcriptional gene regulation (PTGR) suggests an important role for non-coding RNA in the maturing oocyte. (biomedcentral.com)
  • Nuclear receptor coactivators associate in a ligand-dependent manner with estrogen receptors (ER) and other nuclear receptors, and they enhance ligand-dependent transcriptional activation. (bioone.org)
  • Moreover, brief exposure during puberty may induce silent oocyte disruption, which could in turn lead to decreased fecundity rates. (biomedcentral.com)
  • The fact that live-birth rates from oocyte donation in older women are consistent with the age of the donor suggests that oocyte quality is the major factor responsible for reduced fecundability with aging. (arvigen.com)
  • They differ in their maturation stages according to the part of the epididymis from which they have been collected. (encyclopedia.pub)
  • 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)
  • Other attempts to overcome ooplasmic aging have utilized oocyte manipulation at a subcellular level. (arvigen.com)
  • Oocytes were collected from slaughterhouse-derived ovaries, matured in vitro, and injected with frozen-thawed stallion sperm. (bioone.org)
  • Epididymal spermatozoas are often described as immature, immotile, and infertile sperm cells, yet the epididymis is the organ where spermatozoa mature, acquire motility, and become fully fertile. (encyclopedia.pub)
  • A better understanding of the function of this organ and of the chronology of sperm maturation may elucidate the etiological background of many idiopathic subfertilities that are related to disorders in sperm maturation. (encyclopedia.pub)
  • Injection of a MIR21 mimic increased oocyte maturation rate. (biomedcentral.com)
  • When in vitro experimental models are exposed to ATZ, they are faced with increased levels of reactive oxygen species (ROS), cytotoxicity and decreased growth rate at dosages that may vary with cell types. (frontiersin.org)
  • Oocyte arrest at the diplotene stage is maintained in part through the activity of phosphodiesterase enzymes that catalyze the hydrolysis of cyclic adenosine monophosphate (cAMP) into AMP [ 1 , 2 ]. (biomedcentral.com)
  • Methods: Germinal Vesicle (GV) stage oocytes were observed in 120 NMRI mice, aged 4-6 weeks. (ajmb.org)
  • In vitro culture and maturation of Germinal Vesicle (GV) oocytes is an efficient method to generate mature oocytes. (ajmb.org)
  • Early oocytes are also classified as immature (germinal vesicle (GV) or metaphase I (MI) stage). (edu.au)
  • 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)
  • Although the growth of in vitro preantral follicles can result in fertilizable oocytes and successful childbirth 9 , the technique of In Vitro Maturation (IVM) needs to be further enhanced because GV oocytes have a reasonable ability to mature and reach the Metaphase II (MII) stage. (ajmb.org)
  • 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)
  • Oocyte recovery for in vitro applications can be achieved by isolating granulosa-oocyte-complexes from later antral follicles however, the majority of oocytes (≥ 90%) are encapsulated in the earliest, dormant PrFs 5 . (nature.com)
  • 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)
  • 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)
  • In vitro growth (IVG) of dormant primordial ovarian follicles aims to produce mature competent oocytes for assisted reproduction. (nature.com)
  • Success is dependent on optimal in vitro conditions complemented with an understanding of oocyte and ovarian follicle development in vivo. (nature.com)
  • The activation, growth, and development of an ovarian follicle, a process termed ovarian folliculogenesis, is finely regulated by cell-to-cell interactions and coordinated gene expression in the oocyte and surrounding granulosa cells (GCs) 4 . (nature.com)
  • In recent years, numerous attempts have been made to grow and stimulate immature follicles 1,3-6 with the intent to eventually treat infertility attributed to polycystic ovary syndrome, premature ovarian failure, and infertility following cancer treatments 7,8 . (ajmb.org)
  • Ovarian spermatogenesis and suppressed ovarian maturation were observed in the females that exhibited imposex, although no histopathological abnormalities were found in males. (nih.gov)
  • Female-factor infertility can be caused by poor oocyte quality and depleted ovarian reserves. (oncotarget.com)
  • Several potential options are available to preserve fertility in patients who face premature ovarian failure, including immature or mature oocyte and embryo cryopreservation. (cambridge.org)
  • Therefore, this review aims to summarize the achievements of ovary grafting and the potential techniques that have been developed to improve ovarian graft survival. (cambridge.org)
  • The ultrasound determination of ovarian response in embryo donor goats still needs to be proven, especially because the non-invasive technique is mandatory when the embryo collection is done by transcervical route. (embrapa.br)
  • The aim of this study was to investigate the effect of different progestagens during ovarian stimulation on follicular population and oocyte morphological quality in Santa Inês ewes. (embrapa.br)
  • In conclusion, the source of progestagens used during the ovarian stimulation protocol does not affect the follicular population, nor the oocyte quality. (embrapa.br)
  • 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)
  • Embryo production from oocytes derived from advanced preantral follicles developed by IVG has been achieved in porcine, buffalo, ovine, and goat but inconsistently so 11 . (nature.com)
  • 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)
  • The presence of Zp1 , Zp2 , Zp3 and Nobox were not detected, indicating that porcine EPCs are not indicative of mature primordial oocytes. (oncotarget.com)
  • Artificial reproductive technology (ART) such as, germ cell cryopreservation and in vitro embryo production can potentially contribute to species conservation when populations decline to a critically small size 1 . (nature.com)
  • It is based on the number of layers and compactness of cumulus cells surrounding the oocyte, as well as the homogeneity of the ooplasm ( 6 ). (macvetrev.mk)
  • GV oocytes with or without cumulus cells were subjected to IVM in either ESCM, Embryonic Stem Cell Growth Medium (ESGM), or α-minimum essential medium (α-MEM). (ajmb.org)
  • Therefore, these oocytes are a great source for folliculogenesis based studies and embryo production. (ajmb.org)
  • In vitro embryo production. (embrapa.br)
  • Oocyte quality and maturity are the most important determinants of blastocyst developmental competence ( 3 ). (macvetrev.mk)
  • 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)
  • We performed mitochondrial DNA Next Generation Sequencing and determined that one mtDNA variant harbored by EPCs was present in oocytes, preimplantation embryos and somatic tissues over three generations in our mini-pig model indicating the potential germline origin of EPCs. (oncotarget.com)
  • 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)
  • Male-factor infertility can be overcome by a technique called intracytoplasmic sperm injection (ICSI), which directly injects a sperm into an oocyte, and is one of the most widely used treatments in the fertility clinic [ 3 ]. (oncotarget.com)
  • Meanwhile, the Gsα knockout-induced decline in oocyte quality and low developmental potential was partially rescued by antioxidant supplementation. (edu.au)
  • However, only 30-35% of immature oocytes in mammals reach the blastocyst stage ( 2 ). (macvetrev.mk)
  • 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)
  • Embryonic stem cells are an in vitro copy of embryonic cells at the blastocyst stage, called the inner cell mass 18,19 . (ajmb.org)
  • This technique, as an adjuvant treatment for infertility, is of paramount importance for assisted reproductive technology 1,2 . (ajmb.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)
  • Brilliant cresyl blue (BCB) staining is a method used for selection of developmentally competent porcine oocytes, in addition to the standard morphological classification. (macvetrev.mk)
  • 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)
  • The quality of mitochondria and the numbers of copies of its genome, mitochondrial DNA (mtDNA), in oocytes are beginning to be considered, along with other factors, as indicators of oocyte quality, especially in the context of aging [ 5 - 11 ]. (oncotarget.com)
  • An increasing number of women are delaying childbirth, and, since oocyte quality declines dramatically after 35 years of age [ 1 , 2 ], more women are requiring assisted reproductive treatments. (oncotarget.com)
  • This dogma states that female mammals are born with finite numbers of oocytes that decline throughout postnatal life. (cambridge.org)
  • These findings showed that COCs with high morphological characteristics had higher developmental ability compared to COCs with low morphology. (macvetrev.mk)
  • A way to solve this limitation could be to produce large numbers of oocytes, in vitro, from stem cells. (edu.au)
  • Key influencing factors during this transition included the interaction between the extracellular matrix (ECM) and matrix metalloproteinase (MMPs) along with nuclear components such as, histone HIST1H1T (H1.6). (nature.com)
  • 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)
  • 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)
  • formation of cortical granules was examined in superovulated oocytes from three marsupial species, brushtail possums (trichosurus vulpecula) tammar wallabies (macropus eugeniii) and grey short-tailed opossums (monodelphis domestica) and in oocytes obtained during natural cycles in macropus eugenii. (liverpool.ac.uk)
  • In the first part of the study, cumulus-oocytes complexes (COCs) (n=434) were aspirated from 60 ovaries. (macvetrev.mk)
  • Oocytes used for in vitro production are most frequently retrieved from ovaries obtained from slaughterhouses. (macvetrev.mk)
  • GV oocytes are the main units of ovaries which produce a suitable environment for the growth and maturation of oocytes. (ajmb.org)
  • The primary criterion widely used for oocyte quality assessment is morphological classification. (macvetrev.mk)
  • 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)
  • Nuclear receptor coactivators associate in a ligand-dependent manner with estrogen receptors (ER) and other nuclear receptors, and they enhance ligand-dependent transcriptional activation. (bioone.org)
  • 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)
  • In attempt to develop a hormonal protocol more suitable to produce good quality oocytes for use in biotechnologies, an earlier study demonstrated that FSH applied in multiple decreasing doses produced better quality oocytes. (embrapa.br)
  • 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)
  • stability of the acrosome of the brush-tailed possum (trichosurus vulpecula) and tammar wallaby (macropus eugenii) in vitro and after exposure to conditions and agents known to cause capacitation or acrosome reaction of eutherian spermatozoa. (liverpool.ac.uk)
  • It has been established that G6PDH gets inactivated as soon as the oocytes complete their growth ( 4 ). (macvetrev.mk)
  • Oocytes with completed growth phase have blue colored ooplasm and are classified as BCB-positive (BCB+). (macvetrev.mk)
  • It is believed that one of the causes is an early stage of degeneration of oocytes with normal morphology ( 7 ). (macvetrev.mk)
  • Studies involved in optimising these techniques could potentially be applied to human oncofertility and fertility preservation in the future also 3 . (nature.com)
  • Currently, there is no reliable method for measurement of ooplasmic maturation ( 3 ). (macvetrev.mk)