Differential effects of high and low glucose concentrations during lipolysis-like conditions on bovine in vitro oocyte quality, metabolism and subsequent embryo development

Lipolytic metabolic conditions are traditionally associated with elevated non-esterified fatty acid (NEFA) concentrations, but may also be accompanied by hyperglycaemia in obesity or by hypoglycaemia during a negative energy balance status. Elevated NEFA concentrations disrupt oocyte and embryo development and quality, but little is known about whether the effects of lipolytic conditions on oocyte developmental competence are modulated by glucose availability. To answer this, bovine cumulus–oocyte complexes (COCs) were matured under different conditions: physiological NEFA (72 µM) and normal glucose (5.5 mM), pathophysiologically high NEFA (420 µM) and normal glucose, high NEFA and high glucose (9.9 mM), high NEFA and low glucose (2.8 mM). Developmental potential, cumulus expansion and metabolism of COCs exposed to high NEFA and low glucose were affected to a greater extent compared with COCs matured under high NEFA and high glucose conditions. High NEFA and high glucose conditions caused a moderate increase in oocyte reactive oxygen species compared with their high NEFA and low glucose or control counterparts. Blastocyst metabolism and the transcriptome of metabolic and oxidative stress-related genes were not affected. However, both lipolytic conditions associated with hyper- or hypoglycaemia led to surviving embryos of reduced quality with regards to apoptosis and blastomere allocation.

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158 The Effect of Follicular Wave Phase at Time of Ovum Pick-Up on Bovine Oocyte Cytoplasmic Maturation and Developmental Competence

Reproduction Fertility and Development ◽

10.1071/rdv30n1ab158 ◽

2018 ◽

Vol 30 (1) ◽

pp. 218

Author(s):

B. A. Foster ◽

F. A. Diaz ◽

E. J. Gutierrez ◽

K. R. Bondioli

Keyword(s):

Embryo Development ◽

Transvaginal Ultrasound ◽

Oocyte Quality ◽

Developmental Competence ◽

Developmental Potential ◽

Follicular Wave ◽

Wave Phase ◽

Oocyte Collection ◽

Significant Difference

During oocyte collection, follicular wave phase is unknown, although differences in follicle environment may have dramatic effects on oocyte quality. This project was performed to determine whether oocyte collection during different phases of the follicular wave affects oocyte competence. Oocytes were collected via transvaginal ultrasound guided oocyte aspiration from 18 cows, at 4, 8, and 12 days following dominant follicle removal, representing follicle wave emergence, peak, and atresia, respectively (160, 314, and 273 oocytes, respectively). Once recovered, oocytes were graded and assigned to either being held as immature or matured in vitro for 24 h. Oocytes were then stained in Mitotracker deep red, fixed and stained with an anti-IP3R1 primary antibody and an Alexa Fluor 488-conjugated secondary antibody, before being stained with DAPI, to identify mitochondria, inositol triphosphate receptor 1 (IP3R1), and chromatin respectively. Mitochondria were analysed based on cytoplasmic distribution and classified as peripheral (immature), diffuse, central (mature), or sparse. Expression of IP3R1 was measured as corrected total cell fluorescence in Image J (National Institutes of Health, Bethesda, MD, USA). Staining patterns were analysed using ANOVA. A subset of the matured oocytes was stained with Fluo-3 to measure cytoplasmic calcium levels. These oocytes were then parthenogenetically activated before being imaged again to view changes in calcium levels, and presumptive embryos were cultured for 4 days. Fluo staining was measured as intensity levels (none, slight, moderate, high) and differences in development and stain levels were analysed using the Kruskal-Wallis test. Although mitochondria location was unaffected by collection day, it was significantly affected by maturation status (P = 0.0036). However, oocytes showed incomplete mitochondrial maturation, with mitochondria residing in the diffuse orientation in the majority of oocytes. Expression of IP3R1 appeared to be more sensitive to treatment. Expression significantly increased as meiosis proceeded (P = 0.0081) and there was a significant difference in expression between oocyte collection days (P = 0.0026). The interaction between collection day and maturation status also had a significant effect (P = 0.048), with mature oocytes showing an increase in IP3R1 expression, most notable in those collected on Day 4. Oocyte quality had a notable effect on the ability of oocytes to progress through meiosis (P = 0.054) and on mitochondrial location (P = 0.053), with AB oocytes showing better maturation parameters in both respects. Although the day of collection did not affect embryo development, Fluo stain intensity was an indicator of embryo developmental potential (P = 0.053), with oocytes having decreased potential to develop if the initial calcium levels were moderate to high. Results suggest that oocyte collection during wave emergence yields a slight advantage in oocyte quality. Although IP3R1, necessary for Ca2+ spikes during fertilization, indicates competence, high levels of cytoplasmic Ca2+ at the time of activation appear to be detrimental to embryo development.

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P–219 mtDNA content in bovine cumulus cells does not predict oocytés developmental competence

Human Reproduction ◽

10.1093/humrep/deab130.218 ◽

2021 ◽

Vol 36 (Supplement_1) ◽

Author(s):

Á Martíne. Moro ◽

I Lamas-Toranzo ◽

L González-Brusi ◽

A Pérez-Gómez ◽

P Bermejo-Álvarez

Keyword(s):

Cumulus Cell ◽

Cumulus Cells ◽

Oocyte Quality ◽

Blastocyst Stage ◽

Early Embryo ◽

Developmental Competence ◽

Success Rates ◽

Developmental Potential ◽

Mtdna Sequence

Abstract Study question Does cumulus cell mtDNA content correlate with oocyte developmental potential in the bovine model? Summary answer The relative amount of mtDNA content did not vary significantly in oocytes showing different developmental outcomes following IVF What is known already Cumulus cells are closely connected to the oocyte through transzonal projections, serving essential metabolic functions during folliculogenesis. These oocyte-supporting cells are removed and discarded prior to ICSI, thereby constituting an interesting biological material on which to perform molecular analysis aimed to predict oocyte developmental competence. Previous studies have positively associated oocytés mtDNA content with developmental potential in both animal models and women. However, it remains debatable whether mtDNA content in cumulus cells could be used as a proxy to infer oocyte developmental potential. Study design, size, duration Bovine cumulus cells were allocated into three groups according to the developmental potential of the oocyte: 1) oocytes developing to blastocysts following IVF (Bl+Cl+), 2) oocytes cleaving following IVF but arresting their development prior to the blastocyst stage (Bl-Cl+), and 3) oocytes not cleaving following IVF (Bl-Cl-). Relative mtDNA content was analysed in 40 samples/group, each composed by the cumulus cells from one cumulus-oocyte complex (COC). Participants/materials, setting, methods Bovine cumulus-oocyte complexes were obtained from slaughtered cattle and individually matured in vitro (IVM). Following IVM, cumulus cells were removed by hyaluronidase treatment, pelleted, snap frozen in liquid nitrogen and stored at –80 ºC until analysis. Cumulus-free oocytes were fertilized and cultured in vitro individually and development was recorded for each oocyte. Relative mtDNA abundance was determined by qPCR, amplifying a mtDNA sequence (COX1) and a chromosomal sequence (PPIA). Statistical differences were tested by ANOVA. Main results and the role of chance Relative mtDNA abundance did not differ significantly (ANOVA p > 0.05) between the three groups exhibiting different developmental potential (1±0.06 vs. 1.19±0.05 vs. 1.11±0.05, for Bl+Cl+ vs. Bl-Cl+ vs. Bl-Cl-, mean±s.e.m.). Limitations, reasons for caution Experiments were conducted in the bovine model. Although bovine folliculogenesis, monoovulatory ovulation and early embryo development exhibit considerable similarities with that of humans, caution should be taken when extrapolating these data to humans. Wider implications of the findings: The use of molecular markers for oocyte developmental potential in cumulus cells could be used to enhance success rates following single-embryo transfer. Unfortunately, mtDNA in cumulus cells was not found to be a good proxy for oocyte quality. Trial registration number Not applicable

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DNA damage in cumulus cells generated after the vitrification of in vitro matured porcine oocytes and its impact on fertilization and embryo development

Porcine Health Management ◽

10.1186/s40813-021-00235-w ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Alma López ◽

Miguel Betancourt ◽

Yvonne Ducolomb ◽

Juan José Rodríguez ◽

Eduardo Casas ◽

...

Keyword(s):

Dna Damage ◽

Embryo Development ◽

Tail Length ◽

Cumulus Cells ◽

Cell Types ◽

Oocyte Quality ◽

Blastocyst Stage ◽

Developmental Competence ◽

Development Rates

Abstract Background The evaluation of the DNA damage generated in cumulus cells after mature cumulus-oocyte complexes vitrification can be considered as an indicator of oocyte quality since these cells play important roles in oocyte developmental competence. Therefore, the aim of this study was to determine if matured cumulus-oocyte complexes exposure to cryoprotectants (CPAs) or vitrification affects oocytes and cumulus cells viability, but also if DNA damage is generated in cumulus cells, affecting fertilization and embryo development. Results The DNA damage in cumulus cells was measured using the alkaline comet assay and expressed as Comet Tail Length (CTL) and Olive Tail Moment (OTM). Results demonstrate that oocyte exposure to CPAs or vitrification reduced oocyte (75.5 ± 3.69%, Toxicity; 66.7 ± 4.57%, Vitrification) and cumulus cells viability (32.7 ± 5.85%, Toxicity; 7.7 ± 2.21%, Vitrification) compared to control (95.5 ± 4.04%, oocytes; 89 ± 4.24%, cumulus cells). Also, significantly higher DNA damage expressed as OTM was generated in the cumulus cells after exposure to CPAs and vitrification (39 ± 17.41, 33.6 ± 16.69, respectively) compared to control (7.4 ± 4.22). In addition, fertilization and embryo development rates also decreased after exposure to CPAs (35.3 ± 16.65%, 22.6 ± 3.05%, respectively) and vitrification (32.3 ± 9.29%, 20 ± 1%, respectively). It was also found that fertilization and embryo development rates in granulose-intact oocytes were significantly higher compared to denuded oocytes in the control groups. However, a decline in embryo development to the blastocyst stage was observed after CPAs exposure (1.66 ± 0.57%) or vitrification (2 ± 1%) compared to control (22.3 ± 2.51%). This could be attributed to the reduction in both cell types viability, and the generation of DNA damage in the cumulus cells. Conclusion This study demonstrates that oocyte exposure to CPAs or vitrification reduced viability in oocytes and cumulus cells, and generated DNA damage in the cumulus cells, affecting fertilization and embryo development rates. These findings will allow to understand some of the mechanisms of oocyte damage after vitrification that compromise their developmental capacity, as well as the search for new vitrification strategies to increase fertilization and embryo development rates by preserving the integrity of the cumulus cells.

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210 DNA METHYLATION AND HYDROXYMETHYLATION ANALYSIS IN A MODEL OF OOCYTE DIFFERENTIAL DEVELOPMENTAL COMPETENCE IN SHEEP

Reproduction Fertility and Development ◽

10.1071/rdv27n1ab210 ◽

2015 ◽

Vol 27 (1) ◽

pp. 195

Author(s):

L. Masala ◽

D. Bebbere ◽

G. P. Burrai ◽

F. Ariu ◽

L. Bogliolo ◽

...

Keyword(s):

Dna Methylation ◽

Embryo Development ◽

Oocyte Quality ◽

Developmental Competence ◽

Ctcf Binding ◽

Ctcf Binding Site ◽

Global Methylation ◽

Tet Genes ◽

Lower Expression

DNA methylation is an important epigenetic mark that plays a role in gene regulation by the addition of a methyl group to CpG islands in the DNA. Despite being relatively stable in somatic cells, DNA methylation is subject to reprogramming during embryo development and gametogenesis. The aim of this work was to evaluate different aspects of DNA methylation in relation to oocyte quality in the ovine species. A model of differential developmental competence consisting in ovine oocytes and in vitro produced (IVP) blastocysts derived from adult (AD) and prepubertal (PR) donors, was used. The methylation was analysed in terms of: expression of a panel of genes involved in DNA methylation [DNA methyltransferases (DNMTs)] and demethylation [ten-eleven translocation dioxygenases (TET)] in oocytes and blastocysts; global methylation and hydroxymethylation by direct immunofluorescence; locus-specific methylation of 2 imprinted genes by pyrosequencing. Gene relative quantification was performed by RNA reverse transcription followed by real-time PCR. Pools of 10 immature (GV) and in vitro-matured (MII) oocytes and (IVP) blastocysts derived from AD and PR donors (4 replicates per class) were analysed. Lower expression of TET1, TET2, and TET3 was observed in PR GV oocytes (ANOVA; P < 0.05), while no significant differences were found for the enzymes involved in methylation (DNMT1, DNMT3A, DNMT3B; ANOVA; P > 0.05). The levels of all the genes studied showed no significant differences in embryos at blastocyst stage (ANOVA; P > 0.05). Methylation and hydroxymethylation immunostaining were performed in GV and MII oocytes using anti-5-methylcytosine mouse mAb and 5-hydroxymethylcytosine rabbit pAB. High levels of DNA methylation were observed in both AD and PR GV and MII oocytes, while hydroxymethylation immunopositivity was scattered evident throughout the gamete chromatin. Pyrosequencing of bisulfite converted DNA was used to determine the methylation status within differentially methylated regions (DMR) of maternally imprinted H19 (CTCF binding site IV; 11 CpG sites) and paternally imprinted IGF2R (17CpG sites within intron 2). No differences were observed between classes of oocytes for each gene (pools of 40 oocytes per replicate, 3 replicates per class; ANOVA; P > 0.05). Our work shows no differences in the expression of the enzymes involved in methylation, in accordance with the results of global and locus specific methylation analysis. Conversely, we observed lower expression of the TET genes in PR GV oocytes (ANOVA; P > 0.05). TET1, TET2, and TET3, whose expression has never been studied in ovine, generate 5-hydroxymethlcytosine (5hmC) by oxidation of 5-methylcytosine (5mC), and are involved in active DNA demethylation during early embryo development. Our observation of lower expression of the TET genes in lower competence PR GV oocytes suggests that epigenetic mechanisms may affect oocyte quality and paves the way to better understand methylation dynamics during sheep pre-implantation development.

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The Role of MAPK3/1 and AKT in the Acquisition of High Meiotic and Developmental Competence of Porcine Oocytes Cultured In Vitro in FLI Medium

International Journal of Molecular Sciences ◽

10.3390/ijms222011148 ◽

2021 ◽

Vol 22 (20) ◽

pp. 11148

Author(s):

Radek Procházka ◽

Alexandra Bartková ◽

Lucie Němcová ◽

Matej Murín ◽

Ahmed Gad ◽

...

Keyword(s):

Time Course ◽

Cumulus Cell ◽

Cell Communication ◽

Oocyte Quality ◽

Developmental Competence ◽

Control Medium ◽

Developmental Potential ◽

Akt Activation ◽

Expression Of Genes

The developmental potential of porcine oocytes cultured in vitro was remarkably enhanced in a medium containing FGF2, LIF and IGF1 (FLI) when compared to a medium supplemented with gonadotropins and EGF (control). We analyzed the molecular background of the enhanced oocyte quality by comparing the time course of MAPK3/1 and AKT activation, and the expression of genes controlled by these kinases in cumulus-oocyte complexes (COCs) cultured in FLI and the control medium. The pattern of MAPK3/1 activation in COCs was very similar in both media, except for a robust increase in MAPK3/1 phosphorylation during the first hour of culture in the FLI medium. The COCs cultured in the FLI medium exhibited significantly higher activity of AKT than in the control medium from the beginning up to 16 h of culture; afterwards a deregulation of AKT activity occurred in the FLI medium, which was not observed in the control medium. The expression of cumulus cell genes controlled by both kinases was also modulated in the FLI medium, and in particular the genes related to cumulus-expansion, signaling, apoptosis, antioxidants, cell-to-cell communication, proliferation, and translation were significantly overexpressed. Collectively, these data indicate that both MAPK3/1 and AKT are implicated in the enhanced quality of oocytes cultured in FLI medium.

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170 INFLUENCE OF OOCYTE QUALITY AND DIFFERENT MEDIA SUPPLEMENT ON IN VITRO MATURATION, CLEAVAGE, AND EMBRYO DEVELOPMENT OF BUFFALO (BUBALUS BUBALIS) OOCYTES

Reproduction Fertility and Development ◽

10.1071/rdv26n1ab170 ◽

2014 ◽

Vol 26 (1) ◽

pp. 199

Author(s):

M. M. Waheed ◽

K. H. El-Shahat ◽

A. M. Hammam

Keyword(s):

Embryo Development ◽

In Vitro Maturation ◽

Cumulus Cell ◽

Oocyte Quality ◽

Bubalus Bubalis ◽

Poor Quality ◽

Developmental Competence ◽

Control Group ◽

Excellent Quality

A series of 4 factorial-arranged experiments were conducted to study the effect of oocyte quality and different in vitro maturation (IVM) media supplements on IVM, cleavage, and embryo development of buffalo (Bubalus bubalis) oocytes. Buffalo ovaries were collected at a local abattoir in a warm (32–35°C) saline (0.9% NaCl), and oocytes were aspirated using an 18-gauge needle. In experiment 1, oocytes (n = 320) were classified according to the number of cumulus cell layers and morphology of ooplasm as excellent, good, or fair. Oocytes were cultured for IVM, fertilization, and embryo culture (IVMFC) in TCM-199 + 10% FCS. In experiment 2, excellent quality oocytes (n = 237) were subjected to IVM in TCM-199 enriched with either 10% FCS or oestrous buffalo serum (EBS; 20–40 pg mL–1) and then fertilized using frozen–thawed buffalo semen capacitated in Bracket and Oliphant's (BO) medium containing heparin (0.02 mg mL–1) and sodium caffeine benzoate (3.89 mg mL–1). In experiment 3, oocytes (n = 290) were classified into 2 groups; Group 1, without gonadotropins, served as a control; Group 2, in which IVM medium was supplemented with 20 IU mL–1 equine chorionic gonadotropins (eCG). Experiment 4 was carried out to examine the suitable capacitating agent added to BO medium, either heparin or caffeine or both (n = 210 fertilized oocytes). In all experiments (multiple replicates), oocytes (2–6 mm in diameter) were kept at 39°C under 5% CO2 for IVMFC and examined several times for cleavage and embryo development (morula and blastocyst). Statistical analysis was carried out using Chi-squared test. Excellent and good quality oocytes produced a higher (P < 0.05) maturation, cleavage, and morula development rates than poor quality oocytes (70% and 65% v. 33.3%), (50% and 46.2% v. 25%), and (42.9% and 33.3% v. 10%), respectively. Blastocyst production rate was also higher (P < 0.05) for excellent compared with good quality oocytes (28.6% v. 16.7%, respectively). In experiment 2, the IVM and cleavage rates were significantly higher (P < 0.05) in IVM medium plus 10% EBS than those cultured in 10% FCS (73% v. 45% and 50% v. 33.3%, respectively). In experiment 3, the addition of eCG to maturation medium increased (P < 0.05) developmental competence of buffalo oocytes (IVMFC) compared with control medium (16% v. 4%). In experiment 4, the addition of heparin together with caffeine to BO medium produced significantly higher (P < 0.05) cleavage and embryo developmental rates compared with heparin or caffeine alone (56.3% v. 33.3% and 35.7%, respectively; 22.2% v. 10% and 8%, respectively). In conclusion, excellent quality oocytes cultured in IVM medium supplemented with either EBS or eCG and fertilized with capacitated buffalo spermatozoa in BO medium enriched with heparin and caffeine progressively enhanced developmental competence of buffalo oocytes.

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Cellular and Molecular Events that Occur in the Oocyte during Prolonged Ovarian Storage in Sheep

Animals ◽

10.3390/ani10122414 ◽

2020 ◽

Vol 10 (12) ◽

pp. 2414

Author(s):

Alicia Martín-Maestro ◽

Irene Sánchez-Ajofrín ◽

Carolina Maside ◽

Patricia Peris-Frau ◽

Daniela-Alejandra Medina-Chávez ◽

...

Keyword(s):

Dna Fragmentation ◽

Saline Solution ◽

Cumulus Cell ◽

Small Ruminants ◽

Oocyte Quality ◽

Developmental Competence ◽

Developmental Potential ◽

Oocyte Competence ◽

Cell Parameters

For the past two decades, there has been a growing interest in the application of in vitro embryo production (IVP) in small ruminants such as sheep. To improve efficiency, a large number abattoir-derived ovaries must be used, and long distances from the laboratory are usually inevitable when adult animals are used. In that scenario, prolonged sheep ovary transportation may negatively affect oocyte developmental competence. Here, we evaluated the effect of ovary storage time (3, 5, 7, 9, 11 and 13 h) and the medium in which they were transported (TCM199 and saline solution) on oocyte quality. Thus, live/dead status, early apoptosis, DNA fragmentation, reduced glutathione (GSH) and reactive oxygen species (ROS) content, caspase-3 activity, mitochondrial membrane potential and distribution, and relative abundance of mRNA transcript levels were assessed in oocytes. After in vitro maturation (IVM), cumulus cell viability and quality, meiotic and fertilization competence, embryo rates and blastocyst quality were also evaluated. The results revealed that, after 7 h of storage, oocyte quality and developmental potential were significantly impaired since higher rates of dead oocytes and DNA fragmentation and lower rates of viable, matured and fertilized oocytes were observed. The percentage of cleavage, blastocyst rates and cumulus cell parameters (viability, active mitochondria and GSH/ROS ratio) were also decreased. Moreover, the preservation of ovaries in medium TCM199 had a detrimental effect on cumulus cells and oocyte competence. In conclusion, ovary transport times up to 5 h in saline solution are the most adequate storage conditions to maintain oocyte quality as well as developmental capacity in sheep. A strategy to rescue the poor developmental potential of stored oocytes will be necessary for successful production of high-quality embryos when longer ovarian preservation times are necessary.

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Cycloheximide speeds the porcine oocyte nuclear kinetics and retains embryonic developmental potential in the presence of gonadotrophins

Canadian Journal of Animal Science ◽

10.4141/cjas09066 ◽

2010 ◽

Vol 90 (2) ◽

pp. 189-196

Author(s):

X -L. Sun ◽

W -Z. Ma ◽

Y -B. Zhu ◽

Z -H. Wu ◽

L. An ◽

...

Keyword(s):

Embryo Development ◽

Germinal Vesicle ◽

Chorionic Gonadotrophin ◽

Developmental Competence ◽

Electrical Activation ◽

Control Group ◽

Germinal Vesicle Breakdown ◽

Developmental Potential ◽

Oocyte Meiosis

Animal embryo engineering requires large amounts of synchronized mature oocytes in vitro. However, porcine cumulus-oocyte complexes aspirated from 3-8 mm follicles are at different germinal vesicle stages. They reach metaphase II stages asynchronously when cultured in vitro. In this study, we examined the effects of pretreatment with or without cycloheximide (CHX), equine chorionic gonadotrophin (eCG), human chorionic gonadotrophin (hCG), and their combinations on meiotic synchronization and the developmental competence of porcine oocytes in vitro following electrical activation. The COCs were pretreated for 12 h with either control medium (TCM 199), CHX (TCM 199 + CHX), eCG/hCG (TCM 199 + eCG/hCG) or eCG/hCG + CHX (TCM 199 + CHX + eCG/hCG), and then cultured for up to 32 h with TCM199 + eCG/hCG. After 12 h pretreatment, the rates of germinal vesicle breakdown (GVBD) were lower (P < 0.05) in the CHX (8.4%) and eCG/hCG + CHX (1.5%) groups compared with control (55.4%) and eCG/hCG (27.2%) groups. After removal of CHX and culture for an additional 12 h in vitro, the majority of the oocytes were synchronized at the GVBD stage in CHX (75.6%) and eCG/hCG + CHX (65.0%) groups. At additional 32 h of culture, the rate of oocytes in metaphase II in eCG/hCG + CHX group (68.3%) was significantly (P < 0.05) higher than the eCG/hCG group (54.8%), but did not differ from other groups (control: 61.3%, CHX: 58.8%). After electrical activation, the cleavage and blastocyst formation rates in the CHX group (80.3%; 19.5%) were significantly (P < 0.05) lower than those in the control group (95.5%; 45.3%), while no difference was found between eCG/hCG + CHX (82.2%; 34.4%) and control groups. Our data, hence, demonstrate pretreatment with CHX hastened nuclear kinetics of porcine oocytes cultured in vitro; however, embryo development potential was retained only when gonadotrophins is present in the in vitro maturation (IVM) medium. Thus, CHX should be used in the two-step culture systems in combination with gonadotrophins. Key words: Oocyte meiosis, synchronization, cycloheximide, embryo development, pig

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156 EFFECTS OF MORPHOLOGY TYPE OF POLAR BODY ON PORCINE OOCYTE QUALITY AND DEVELOPMENTAL POTENTIAL AFTER IN VITRO FERTILIZATION

Reproduction Fertility and Development ◽

10.1071/rdv26n1ab156 ◽

2014 ◽

Vol 26 (1) ◽

pp. 192

Author(s):

L. Cai ◽

E. Kim ◽

S. U. Hwang ◽

J. D. Yoon ◽

Y. Jeon ◽

...

Keyword(s):

Polar Body ◽

Oocyte Quality ◽

Developmental Competence ◽

Penicillin G ◽

Cleavage Rate ◽

Developmental Potential ◽

Vitro Fertilization ◽

First Polar Body

Evaluation of morphology of first polar body (1st PB) could be a method for the oocyte's quality and developmental competence. The developmental potential of oocyte with fragmented PB after in vitro maturation (IVM) is a controversial issue. The aim of this study is to investigate the effects of PB morphology type on oocyte quality and developmental competence after IVF. Porcine ovaries were obtained from prepubertal gilts at a local slaughterhouse and transported to the laboratory within 2 h in physiological saline supplemented with 100 IU mL–1 penicillin G and 100 mg mL–1 streptomycin sulfate. The cumulus–oocyte complexes (COC) were aspirated using an 18-gauge needle attached to a 10-mL disposable syringe from superficial follicles 3 to 6 mm in diameter followed by IVM. After IVM, oocytes were classified into 3 types as follows, oocytes with normal PB (A type), oocytes with a little of fragmented PB (B type), and oocytes with separated 2 PBs (C type), respectively. As classification of PB types, we analysed the distribution ratio of each PB type after IVM, and then performed IVF for analysis of fertilization rate and developmental potential. The ratio of oocyte with A type (73%) was significantly (P < 0.05) higher than that of B type (24.5%) or C type (2.5%) after IVM. Only mature oocytes were selected from A and B type and were subjected to IVF because of a small number of oocytes with C type. In the IVF experiment, the efficiency of monospermy and fertilization were significantly higher in oocytes of A type (46.7%) than those of type B (20.0%). The cleavage rate of oocytes with A type (63.9%) was significantly (P < 0.05) higher than the oocytes with B type (43.8%). Embryonic developmental competence to the blastocyst stage after IVF was significantly (P < 0.05) higher in the A-type oocytes (26.3%) than in the B-type oocytes (16.9%). The levels of glutathione and reactive oxygen species were not affected by the morphological classification of the PB. In summary, these results suggest that polar body morphology could be a marker of oocyte quality after IVM. We are currently studying gene expression of each oocytes and blastocysts. This work was supported, in part, by a grant from the Next-Generation BioGreen 21 Program (No. PJ00956901), Rural Development Administration, and the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2012R1A1A4A01004885, NRF-2013R1A2A2A04008751), Republic of Korea.

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Evaluation of bovine zona pellucida characteristics in polarized light as a prognostic marker for embryonic developmental potential

Reproduction ◽

10.1530/rep-10-0471 ◽

2011 ◽

Vol 141 (6) ◽

pp. 779-787 ◽

Cited By ~ 13

Author(s):

M Koester ◽

A Mohammadi-Sangcheshmeh ◽

M Montag ◽

F Rings ◽

T Schimming ◽

...

Keyword(s):

Zona Pellucida ◽

Polarized Light ◽

Oocyte Quality ◽

Developmental Competence ◽

Blue Staining ◽

Developmental Potential ◽

Preimplantation Embryo Development ◽

Intensity Parameters ◽

Bovine Oocytes

It has previously been demonstrated that zona pellucida imaging of human oocytes using polarized light microscopy is a clinically applicable method for the noninvasive assessment of oocyte quality. This study was designed to investigate whether zona pellucida characteristics of bovine oocytes and zygotes in polarized light may similarly serve as a useful marker for developmental competence in bovine reproductive biotechnologies. Zona birefringence intensity parameters of 2862 oocytes/zygotes were objectively evaluated with an automatic analysis system and correlated with oocyte/zygote quality. In detail, immature oocytes of good quality assessed with brilliant cresyl blue staining showed significantly lower zona birefringence than poor-quality counterparts (P<0.001). Afterin vitromaturation and classification according to maturational status, the birefringence intensity parameters were significantly different in those oocytes that reached metaphase II compared with arrested stages (P<0.001). Following either parthenogenetic activation or IVF with subsequentin vitroculture in a well-of-the-well system until day 9, superior development as determined by cleavage, blastocyst formation, and hatching ability was associated with lower zona birefringence intensity parameters. When early zygote-stage embryos were selected and assorted in groups based on zona birefringence (high/medium/low), the group of embryos derived from high-birefringence zygotes displayed a significantly compromised developmental potential compared with low-birefringence zygotes. These results clearly show that developmentally competent bovine oocytes/zygotes exhibit lower zona birefringence intensity parameters. Therefore, birefringence imaging of zona pellucida is a suitable technique to predict bovine preimplantation embryo development.

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