Analysis of maturation dynamics and developmental competence of in vitro matured oocytes under time-lapse monitoring

Abstract Background To improve the developmental competence of in vitro cultured oocytes, extensive literature focused on maturation rate improvement with different additives in culture medium, while studies investigating the maturation dynamics of oocytes during in vitro maturation (IVM) and the influencing factors on oocyte viability are scarce. Methods The study involved a retrospective observation by time-lapse monitoring of the IVM process of 157 donated GV oocytes from 59 infertile couples receiving ICSI in 2019, in Tongji Hospital, Wuhan, China. The GV oocytes derived from controlled ovarian hyperstimulation (COH) cycles underwent rescue IVM (R-IVM), and the maturation dynamics, including GVBD time (GV-MI), time from GVBD to maturation (MI-MII), maturation time (GV-MII), and MII arrest duration (MII-ICSI), were recorded by time-lapse monitoring. The matured oocytes were inseminated at different MII arrest points and subsequent embryo developments were assessed. The effects of baseline clinical characteristics, oocyte diameters, and maturation dynamics on the developmental competence of the oocytes were also analyzed. Results Totally, 157 GV oocytes were collected. GVBD happened in 111 oocytes, with a median GV-MI duration of 3.7 h. The median MI-MII duration was 15.6 h and the median GV-MII duration was 19.5 h. The maturation rate reached 56.7% at 24 h and 66.9% at 48 h, and the clinical factors, including patient age, FSH level, AMH level, ovarian stimulation protocol, and serum estradiol and progesterone levels on hCG trigger day, showed no effects on the 24-h maturation rate. The normal fertilization rate of oocytes resuming meiosis within 8 h and matured within 24 h was significantly higher than that of oocytes resuming meiosis after 8 h and matured after 24 h. Furthermore, among those oocytes matured within 24 h, the high-quality embryo formation rate of oocytes resuming meiosis within 4.5 h and matured within 19 h was significantly higher. All stated time was measured from the start point of IVM. Additionally, for oocytes from patients with serum progesterone levels less than 1 ng/ml on hCG trigger day, the high-quality embryo formation rate was significantly increased. Conclusion R-IVM technology could increase the available embryos for patients in routine COH cycles, but excessive culture beyond 24 h is not recommended. GV-MI duration of the oocyte, recorded by time-lapse system, and serum progesterone levels of patients on hCG trigger day can significantly affect the developmental potential of the IVM oocytes.

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The Impact of In vitro Oocyte Maturity on Developmental Potential of Embryos Derived from Controlled Ovarian Stimulation Cycles

International Journal of Medical Laboratory ◽

10.18502/ijml.v6i1.509 ◽

2019 ◽

Author(s):

Fatemeh Montazeri ◽

Ali Mohammad Foroughmand ◽

Seyed Mehdi Kalantar ◽

Abbas Aflatoonian ◽

Ali Mohammad Khalili

Keyword(s):

Formation Rate ◽

Developmental Competence ◽

Control Group ◽

Developmental Potential ◽

Immature Oocytes ◽

Embryo Formation ◽

Significant Difference ◽

The Impact

Background and Aims: One of the major subjects for improving in vitro fertilization (IVF) outcome is the quantity and quality of retrieved oocytes. In vitro maturation (IVM) provides an opportunity for using immature oocytes routinely discarded in clinics. This study aimed at evaluating the quality of embryos derived from in vivo and rescue in vitro matured oocytes. Materials and Methods: Totally, 462 immature oocytes as cases and 466 mature (MII) oocytes as controls were included for study of their developmental competence. Oocytes underwent intracytoplasmic sperm injection insemination and then denuded oocytes were microscopically assessed regarding cytoplasmic and nuclear maturity and quality. Results: The morphological assessments showed fertilization rate of 60.9 and 61.4%, the embryo formation rate of 86.7% and 90.9% and arresting rate of 27.3% and 25.6% for the case and control oocytes, respectively. Evaluating embryo quality in the cleavage stage indicated that 63% of the embryos in the case group and 68% of the embryos in the control group were of good quality. There was no significant difference between fertility rate and arresting rate of oocytes matured in both groups, although the embryo formation rate and the quality of embryos differed significantly. Conclusions: Our findings suggest that IVM is a valuable and practical option for patients who had to cancel IVF treatment cycles because of severe responses or resistance to routine hormonal therapies or those with low functional ovarian reserve.

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237 THE EFFECTS OF BULLS AND X-SORTING OF SPERM ON THE ACCURACY OF NONINVASIVE CRITERIA TO PREDICT BLASTOCYST FORMATION OF IN VITRO-PRODUCED BOVINE EMBRYOS

Reproduction Fertility and Development ◽

10.1071/rdv27n1ab237 ◽

2015 ◽

Vol 27 (1) ◽

pp. 208

Author(s):

S. Matoba ◽

T. Somfai ◽

T. Nagai ◽

M. Geshi

Keyword(s):

Formation Rate ◽

Calf Serum ◽

Time Lapse ◽

Blastocyst Stage ◽

Developmental Competence ◽

Bovine Embryos ◽

Blastocyst Formation ◽

Blastocyst Development ◽

Chi Square

Previously, an early first cleavage and a second cleavage after IVF with a normal cleavage pattern defined by even blastomeres without fragments or protrusions was found to be a potent marker for the selection of embryos with high developmental competence (Sugimura et al. 2012 PLoS ONE 7, e36627). The aim of this study was to investigate the effects of bulls and X-sorting of sperm on the ability of these simple noninvasive markers to predict the potency of bovine IVF embryos to develop to the blastocyst stage in vitro. Immature oocytes were matured in TCM199 supplemented with 0.02 armour unit mL–1 FSH and 5% calf serum at 38.5°C in 5% CO2 and 95% air for 22 to 23 h. After maturation, oocytes were inseminated with either of non-sorted frozen-thawed sperm from 3 bulls (A–C) or X-sorted sperm of bull A. Putative zygotes were cultured (IVC) in CR1aa medium supplemented with 5% calf serum and 0.25 mg mL–1 linoleic acid albumin at 38.5°C in 5% CO2, 5% O2, and 90% N2 for 216 h. Embryo kinetics were observed individually by time-lapse cinematography (CCM-1.3Z; Astec, Fukuoka, Japan; Sugimura et al. 2010 Biol. Reprod. 83, 970–978). First and second cleavage kinetics and pattern were categorized according to Sugimura et al. (2012). For each bull, blastocyst development from embryos possessing the following 3 selection markers was compared: (marker 1) the first cleavage within 28 h after IVF, (marker 2) marker 1 combined with 2 even blastomeres without fragments or protrusions, and (marker 3) marker 2 combined with the second cleavage within 50 h after IVF with ≥6 even blastomeres without fragments or protrusions, respectively. Data were analysed by the Yates' corrected chi-square test. A total of 823 oocytes were used in at least 3 replications. When non-sorted sperm was used for IVF, there was not difference (P > 0.05) in total blastocyst formation rates on Day 8 (Day 0 = IVF) among bulls (ranging between 49.5 and 60.8%); however, blastocyst formation rate of embryos generated from X-sorted sperm of bull A (39.5%) was lower (P < 0.05) compared with other groups despite of similar cleavage rates. Embryos having marker 3 criteria developed to the blastocysts stage at significantly higher rates than those having marker 1 criteria in case of non-sorted sperm of bulls A, B, C, and X-sorted sperm of bull A (75.9, 87.0, 90.0, and 75.0% v. 59.5, 62.2, 63.6, and 46.3%, respectively). In groups produced from non-sorted sperm of bulls A, B, C, and X-sorted sperm of bull A, blastocyst development rates of embryos with marker 2 criteria (73.7, 75.0, 90.0, and 65.8%, respectively) were higher (P < 0.05) than those of embryos having marker 1 criteria but did not differ significantly from those with marker 3 criteria. Our results reveal that a first cleavage within 28 h after IVF to 2 even blastomeres without fragments or protrusions are potent predictive markers of the developmental competence of bovine embryos to the blastocyst stage regardless of bulls and sperm sorting.Research was partly supported by JSPS KAKENHI (26450388).

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154 THE EFFECT OF ZINC ON PORCINE IN VITRO MATURATION AND SUBSEQUENT EMBRYONIC DEVELOPMENT AFTER IN VITRO FERTILIZATION

Reproduction Fertility and Development ◽

10.1071/rdv26n1ab154 ◽

2014 ◽

Vol 26 (1) ◽

pp. 191

Author(s):

Y. Jeon ◽

J. D. Yoon ◽

L. Cai ◽

S. U. Hwang ◽

E. Kim ◽

...

Keyword(s):

Embryonic Development ◽

Inductively Coupled Plasma ◽

In Vitro Maturation ◽

Formation Rate ◽

Developmental Competence ◽

Developmental Potential ◽

Vitro Fertilization ◽

Nuclear Maturation ◽

Significant Difference

Zinc (Zn) is one of the abundant transition metals in biology and is an essential component of most cells. However, there are few reports about the effect of Zn in porcine oocytes. The objective was to investigate the effects of supplementary Zn during in vitro maturation (IVM) of porcine oocytes. We investigated nuclear maturation, intracellular glutathione (GSH) levels, reactive oxygen species (ROS) levels, and subsequent embryonic development after IVF. Before the experiment, Zn concentrations in IVM medium and body fluids were measured using inductively coupled plasma spectrophotometer (sensitivity: 1 μM) and treatment concentrations were determined. Zinc concentration was 12.6 μM in porcine plasma and 12.9 μM in porcine follicular fluid. We confirmed that Zn was not detected in IVM medium. A total of 541 cumulus–oocyte complexes (COC) were used for the evaluation of nuclear maturation. The COC were matured in TCM-199 medium supplemented with various concentrations of Zn (0, 6, 12, 18, and 24 μM). After 44 h of IVM, no significant difference was observed in all groups (metaphase II rate: 85.7, 88.7, 90.4, 90.3, and 87.2%, respectively). A total of 100 matured oocytes were examined for the effects of different Zn concentrations (0, 6, 12, 18, and 24 μM) on porcine oocyte intracellular GSH and ROS levels, which were measured through fluorescent staining and image analysis program. The groups of 12, 18, and 24 μM showed a significant (P < 0.05) increase in intracellular GSH levels (1.45, 1.67, and 1.78, respectively) compared with the control and 6 μM group (1.00 and 1.08, respectively). The intracellular ROS level of oocytes matured with 12, 18, and 24 μM (0.82, 0.68, and 0.55) were significantly (P < 0.05) decreased compared with the control and 6 μM groups (1.00 and 1.03, respectively). Finally, the developmental competence of oocytes matured with different concentrations of Zn (0, 6, 12, 18, and 24 μM) was evaluated after IVF. There were no significantly different in cleavage rates. However, cleavage patterns and blastocyst (BL) formation were different. Fragmented embryo ratio of the 12 μM group (14.9%) was significantly lower than that of the other groups (control, 6, 18, and 24 μM: 26.4, 17.8, 18.4, and 18.0%, respectively). Oocytes treated with 12 μM Zn during IVM had a significantly higher BL formation rate (28.2%) after IVF compared with the control (19.8%). In conclusion, these results indicate that Zn treatment as body fluid concentration during IVM improved the developmental potential of IVF in porcine embryos by increasing the intracellular GSH concentration and decreasing the ROS level. This work was supported, in part, by a grant from the Next-Generation Bio Green 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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254. Effect of donor age and follicle size on oocyte developmental competence in the pig

Reproduction Fertility and Development ◽

10.1071/srb05abs254 ◽

2005 ◽

Vol 17 (9) ◽

pp. 102

Author(s):

M. A. Bagg ◽

M. B. Nottle ◽

C. G. Grupen ◽

D. T. Armstrong

Keyword(s):

In Vitro Maturation ◽

Formation Rate ◽

Calcium Ionophore ◽

Developmental Competence ◽

Oocyte Developmental Competence ◽

Embryo Formation ◽

Arcsine Transformation ◽

Follicle Size ◽

Post Hoc

Oocytes utilised for in vitro embryo production (IVP) are typically derived from 3–8 mm ovarian follicles of slaughtered pre-pubertal pigs. Following in vitro maturation (IVM), pre-pubertal oocytes display lower developmental competence (DC) than adult oocytes. The aim of this study was to determine the proportion of follicles 3, 4, and 5–8 mm in diameter on the surface of pre-pubertal and adult ovaries, and assess DC of corresponding oocytes. Oocytes were matured for 46 h in modified medium 199. Mature oocytes from the three follicle size cohorts were activated with calcium ionophore to assess blastocyst embryo formation rate. Data were subjected to arcsine transformation, ANOVA and the Tukey post-hoc test. Compared with adult ovaries, pre-pubertal ovaries contained a higher proportion of 3 mm follicles (46 ± 4 v. 72 ± 4%, P<0.01), but a lower proportion of 4 mm (33 ± 3 v. 22 ± 3%, P<0.01) and 5–8 mm follicles (21 ± 5 v. 6 ± 2%, P<0.01). Adult oocytes from the three follicle sizes displayed similar DC (41±2% to 47±3%). DC of pre-pubertal oocytes improved with increasing follicle size (3 mm < 4 mm < 5–8 mm; 12±4%, 27±8% and 50±8%, respectively; P < 0.05). In conclusion, the predominance of 3 mm follicles accounts for the low DC of oocytes from pre-pubertal donors compared with adult donors. Further research is required to understand DC acquisition in pre-pubertal pig oocytes from the smaller follicles <5mm in diameter.

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Artificial oocyte activation and human failed-matured oocyte vitrification followed by in vitro maturation

Zygote ◽

10.1017/s0967199411000530 ◽

2011 ◽

Vol 21 (1) ◽

pp. 71-76 ◽

Cited By ~ 9

Author(s):

Y. Liu ◽

Y.X. Cao ◽

Z.G. Zhang ◽

Q. Xing

Keyword(s):

Embryonic Development ◽

Formation Rate ◽

Germinal Vesicle ◽

Early Embryonic Development ◽

Oocyte Activation ◽

High Quality ◽

Oocyte Vitrification ◽

Embryo Formation ◽

Artificial Oocyte Activation

SummaryThe investigation presented in this paper was conducted on the effect of oocytes activation on frozen–thawed human immature oocytes followed by in vitro maturation (IVM). A total of 386 failed-matured oocytes (germinal vesicle (GV) and metaphase I (MI) stages) was randomly divided into two groups: fresh group and vitrification group, GV group and MI group, respectively). The matured oocytes were subject to intracytoplasmic sperm injection (ICSI) after IVM had been carried out. The vitrification group was randomly divided into two groups: controlled and artificial oocyte activation (AOA). The injected oocytes in the controlled group were cultured in cleavage medium. The AOA group oocytes were activated by exposing them to 7% anhydrous alcohol for 6 min then cultured in cleavage medium as well. The rates of fertilization and early embryonic development were compared between the controlled and AOA groups. In MI vitrification group, the high-quality embryo formation rate and blastocyst formation rate were significantly higher in the AOA group than in the controlled group (P < 0.01). In the GV vitrification group, the high-quality embryo formation rate was significantly higher in the AOA group than in the controlled group (P < 0.05). These results indicate that AOA may be good for early embryonic development of vitrified immature human oocytes.

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Cotreatment with RepSox and LBH589 improves the in vitro developmental competence of porcine somatic cell nuclear transfer embryos

Reproduction Fertility and Development ◽

10.1071/rd17543 ◽

2018 ◽

Vol 30 (10) ◽

pp. 1342 ◽

Cited By ~ 4

Author(s):

Zhao-Bo Luo ◽

Long Jin ◽

Qing Guo ◽

Jun-Xia Wang ◽

Xiao-Xu Xing ◽

...

Keyword(s):

Somatic Cell ◽

Somatic Cell Nuclear Transfer ◽

Nuclear Transfer ◽

Formation Rate ◽

Epigenetic Reprogramming ◽

Developmental Competence ◽

Abnormal Development ◽

Control Group ◽

Blastocyst Formation

Accumulating evidence suggests that aberrant epigenetic reprogramming and low pluripotency of donor nuclei lead to abnormal development of cloned embryos and underlie the inefficiency of mammalian somatic cell nuclear transfer (SCNT). The present study demonstrates that treatment with the small molecule RepSox alone upregulates the expression of pluripotency-related genes in porcine SCNT embryos. Treatment with the histone deacetylase inhibitor LBH589 significantly increased the blastocyst formation rate, whereas treatment with RepSox did not. Cotreatment with 12.5 μM RepSox and 50 nM LBH589 (RepSox + LBH589) for 24 h significantly increased the blastocyst formation rate compared with that of untreated embryos (26.9% vs 8.5% respectively; P < 0.05). Furthermore, the expression of pluripotency-related genes octamer-binding transcription factor 4 (NANOG) and SRY (sex determining region Y)-box 2 (SOX2) were found to significantly increased in the RepSox + LBH589 compared with control group at both the 4-cell and blastocyst stages. In particular, the expression of NANOG was 135-fold higher at the blastocyst stage in the RepSox + LBH589 group. Moreover, RepSox + LBH589 improved epigenetic reprogramming. In summary, RepSox + LBH589 increases the expression of developmentally important genes, optimises epigenetic reprogramming and improves the in vitro development of porcine SCNT embryos.

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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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Induction of autophagy protects against extreme hypoxia-induced damage in porcine embryo

Reproduction ◽

10.1530/rep-20-0311 ◽

2021 ◽

Vol 161 (4) ◽

pp. 353-363

Author(s):

Mun-Hyeong Lee ◽

Pil-Soo Jeong ◽

Bo-Woong Sim ◽

Hyo-Gu Kang ◽

Min Ju Kim ◽

...

Keyword(s):

Oxygen Tension ◽

Early Phase ◽

Inner Cell Mass ◽

Formation Rate ◽

Cell Mass ◽

Female Reproductive Tract ◽

Developmental Competence ◽

Early Embryos ◽

Developmental Parameters

In the mammalian female reproductive tract, physiological oxygen tension is lower than that of the atmosphere. Therefore, to mimic in vivo conditions during in vitro culture (IVC) of mammalian early embryos, 5% oxygen has been extensively used instead of 20%. However, the potential effect of hypoxia on the yield of early embryos with high developmental competence remains unknown or controversial, especially in pigs. In the present study, we examined the effects of low oxygen tension under different oxygen tension levels on early developmental competence of parthenogenetically activated (PA) and in vitro-fertilized (IVF) porcine embryos. Unlike the 5% and 20% oxygen groups, exposure of PA embryos to 1% oxygen tension, especially in early-phase IVC (0–2 days), greatly decreased several developmental competence parameters including blastocyst formation rate, blastocyst size, total cell number, inner cell mass (ICM) to trophectoderm (TE) ratio, and cellular survival rate. In contrast, 1% oxygen tension did not affect developmental parameters during the middle (2–4 days) and late phases (4–6 days) of IVC. Interestingly, induction of autophagy by rapamycin treatment markedly restored the developmental parameters of PA and IVF embryos cultured with 1% oxygen tension during early-phase IVC, to meet the levels of the other groups. Together, these results suggest that the early development of porcine embryos depends on crosstalk between oxygen tension and autophagy. Future studies of this relationship should explore the developmental events governing early embryonic development to produce embryos with high developmental competence in vitro.

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Defective zonae pellucidae in Zp2-null mice disrupt folliculogenesis, fertility and development

Development ◽

10.1242/dev.128.7.1119 ◽

2001 ◽

Vol 128 (7) ◽

pp. 1119-1126 ◽

Cited By ~ 6

Author(s):

T.L. Rankin ◽

M. O'Brien ◽

E. Lee ◽

K. Wigglesworth ◽

J. Eppig ◽

...

Keyword(s):

Zona Pellucida ◽

Embryonic Stem ◽

Single Copy ◽

Targeted Mutagenesis ◽

Developmental Competence ◽

Normal Male ◽

Null Mouse ◽

Developmental Potential ◽

Early Embryos

All vertebrate eggs are surrounded by an extracellular matrix. This matrix is known as the zona pellucida in mammals and is critically important for the survival of growing oocytes, successful fertilization and the passage of early embryos through the oviduct. The mouse zona pellucida is composed of three glycoproteins (ZP1, ZP2 and ZP3), each encoded by a single copy gene. Using targeted mutagenesis in embryonic stem cells, Zp2-null mouse lines have been established. ZP1 and ZP3 proteins continue to be synthesized and form a thin zona matrix in early follicles that is not sustained in pre-ovulatory follicles. The abnormal zona matrix does not affect initial folliculogenesis, but there is a significant decrease in the number of antral stage follicles in ovaries isolated from mice lacking a zona pellucida. Few eggs are detected in the oviduct after stimulation with gonadotropins, and no two-cell embryos are recovered after mating Zp2-null females with normal male mice. The structural defect is more severe than that observed in Zp1-null mice, which have decreased fecundity, but not quite as severe as that observed in Zp3-null mice, which never form a visible zona pellucida and are sterile. Although zona-free oocytes matured and fertilized in vitro can progress to the blastocyst stage, the developmental potential of blastocysts derived from either Zp2- or Zp3-null eggs appears compromised and, after transfer to foster mothers, live births have not been observed. Thus, in addition to its role in fertilization and protection of early embryos, these data are consistent with the zona pellucida maintaining interactions between granulosa cells and oocytes during folliculogenesis that are critical to maximize developmental competence of oocytes.

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Transcriptome dynamics in early in vivo developing and in vitro produced porcine embryos

10.21203/rs.3.rs-73275/v2 ◽

2020 ◽

Author(s):

Vera A van der Weijden ◽

Meret Schmidhauser ◽

Mayuko Kurome ◽

Johannes Knubben ◽

Veronika L Flöter ◽

...

Keyword(s):

Signaling Pathways ◽

Early Stage ◽

Developmental Competence ◽

Molecular Signaling ◽

Developmental Potential ◽

Stage Of Development ◽

Molecular Signaling Pathways ◽

Canonical Pathways

Abstract Background: The transcriptional changes around the time of embryonic genome activation in pre-implantation embryos indicate that this process is highly dynamic. In vitro produced porcine blastocysts are known to be less competent than in vivo developed blastocysts. To understand the conditions that compromise developmental competence of in vitro embryos, it is crucial to evaluate the transcriptional profile of porcine embryos during pre-implantation stages. In this study, we investigated the transcriptome dynamics in in vivo developed and in vitro produced 4-cell embryos, morulae and hatched blastocysts.Results: In vivo developed and in vitro produced embryos displayed largely similar transcriptome profiles during development. Enriched canonical pathways from the 4-cell to the morula transition that were shared between in vivo developed and in vitro produced embryos included oxidative phosphorylation, tRNA charging, and EIF2 signaling. The shared canonical pathways from the morula to the hatched blastocyst transition were 14-3-3-mediated signaling, signaling of Rho family GTPases, and NRF2-mediated oxidative stress response. The in vivo developed and in vitro produced hatched blastocysts were compared to identify molecular signaling pathways indicative of lower developmental competence of in vitro produced hatched blastocysts. A higher metabolic rate and expression of the arginine transporter SLC7A1 were found in in vitro produced hatched blastocysts.Conclusions: Our findings suggest that embryos with compromised developmental potential are arrested at an early stage of development, while embryos developing to the hatched blastocyst stage display largely similar transcriptome profiles, irrespective of the embryo source. The hatched blastocysts derived from the in vitro fertilization-pipeline showed an enrichment in molecular signaling pathways associated with lower developmental competence, compared to the in vivo developed embryos.

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