scholarly journals Chaetocin Improves Pig Cloning Efficiency by Enhancing Epigenetic Reprogramming and Autophagic Activity

2020 ◽  
Vol 21 (14) ◽  
pp. 4836
Author(s):  
Pil-Soo Jeong ◽  
Bo-Woong Sim ◽  
Soo-Hyun Park ◽  
Min Ju Kim ◽  
Hyo-Gu Kang ◽  
...  
Keyword(s):  
Formation Rate ◽  
Dna Methyltransferases ◽  
Epigenetic Reprogramming ◽  
Developmental Competence ◽  
Hatching Rate ◽  
Mrna Levels ◽  
Transgenic Pigs ◽  
Cleavage Rate ◽  
Autophagic Activity

Efficient epigenetic reprogramming is crucial for the in vitro development of mammalian somatic cell nuclear transfer (SCNT) embryos. The aberrant levels of histone H3 lysine 9 trimethylation (H3K9me3) is an epigenetic barrier. In this study, we evaluated the effects of chaetocin, an H3K9me3-specific methyltransferase inhibitor, on the epigenetic reprogramming and developmental competence of porcine SCNT embryos. The SCNT embryos showed abnormal levels of H3K9me3 at the pronuclear, two-cell, and four-cell stages compared to in vitro fertilized embryos. Moreover, the expression levels of H3K9me3-specific methyltransferases (suv39h1 and suv39h2) and DNA methyltransferases (DNMT1, DNMT3a, and DNMT3b) were higher in SCNT embryos. Treatment with 0.5 nM chaetocin for 24 h after activation significantly increased the developmental competence of SCNT embryos in terms of the cleavage rate, blastocyst formation rate, hatching rate, cell number, expression of pluripotency-related genes, and cell survival rate. In particular, chaetocin enhanced epigenetic reprogramming by reducing the H3K9me3 and 5-methylcytosine levels and restoring the abnormal expression of H3K9me3-specific methyltransferases and DNA methyltransferases. Chaetocin induced autophagic activity, leading to a significant reduction in maternal mRNA levels in embryos at the pronuclear and two-cell stages. These findings revealed that chaetocin enhanced the developmental competence of porcine SCNT embryos by regulating epigenetic reprogramming and autophagic activity and so could be used to enhance the production of transgenic pigs for biomedical research.

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

2018 ◽  
Vol 30 (10) ◽  
pp. 1342 ◽  
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.

Effects of milrinone and butyrolactone-I on porcine oocyte meiotic progression and developmental competence

2006 ◽  
Vol 18 (3) ◽  
pp. 309 ◽  
Author(s):  
Christopher G. Grupen ◽  
Maggie Fung ◽  
David T. Armstrong
Keyword(s):  
Formation Rate ◽  
Inhibitory Effect ◽  
Cell Number ◽  
Developmental Competence ◽  
In Vitro Fertilisation ◽  
Cleavage Rate ◽  
Meiotic Progression ◽  
Porcine Oocyte ◽  
Type 3

Inappropriate coordination of oocyte nuclear and cytoplasmic maturation is thought to contribute to the poor efficiency of embryo production in vitro. With the aim of improving this coordination, the effects of milrinone, an inhibitor of type 3 phosphodiesterases, and butyrolactone-I, a selective inhibitor of cdc2 kinases, on porcine oocyte maturation were investigated. Oocytes recovered from slaughterhouse-derived ovaries of prepubertal animals were treated with the inhibitors for 24 h. At concentrations of 50 and 250 μm, milrinone reversibly inhibited meiotic progression in 57% and 71% of oocytes, respectively. The presence or absence of milrinone in the medium used to wash oocytes for 30 min did not alter the inhibitory effect of the 24 h treatment. At concentrations of 25 and 50 μm, butyrolactone-I inhibited meiotic progression in 61% and 66% of oocytes, respectively, but the effect was not fully reversible in the absence of follicle-stimulating hormone (FSH). The presence of FSH during the butyrolactone-I treatment period increased the ability of oocytes to subsequently complete meiosis at 44 h without changing the inhibitory effect at 24 h. Following in vitro fertilisation at 44 and 50 h, treatment with butyrolactone-I and milrinone, alone or in combination, did not alter embryo cleavage rate, blastocyst formation rate or blastocyst cell number. Despite the different actions of milrinone and butyrolactone-I, the present study demonstrates that these reagents inhibit meiotic progression to a similar extent in the presence of FSH while maintaining developmental competence in porcine oocytes.

Enhancement of Developmental Competence of Immature Oocytes Supplemented with Growth Factors in Culture Media 

2021 ◽  
Author(s):  
Sonia B. Umdor ◽  
M. Karunakaran ◽  
D.K. Mandal ◽  
A. Santra ◽  
Subrata K. Das
Keyword(s):  
Growth Factors ◽  
Culture Media ◽  
Formation Rate ◽  
Developmental Competence ◽  
Blastocyst Formation ◽  
Mammalian Development ◽  
Cleavage Rate ◽  
Early Mammalian Development ◽  
Excellent Source

Background: In vitro embryo production is a valuable tool for understanding early mammalian development, therapeutic applications, excellent source for research in the field of developmental biology and production of valuable animals. The purpose of this study is to improve the production of in vitro cattle embryos using fibroblast and platelet derived growth factor as media supplement. Methods: Ovaries were collected from local abattoir in 0.9% saline (30-35°C) supplemented with antibiotics. Cumulus oocyte complexes were aspirated, washed 5-6 times and placed in maturation media supplemented with growth factors and cultured in 5% CO2 incubator at 38.5°C with maximum humidity. After 24 h oocytes were co-incubated with in vitro capacitated sperms for fertilization for 15-18 h and then presumptive zygotes were cultured for embryo development. Cleavage was observed after 40-42 h and embryos were co-cultured with oviductal cells for 7-9 days. Result: The highest cleavage and blastocyst formation rates were 55.93 ± 4.75, 57.06 ± 4.78, 51.24 ± 4.12 and 3.26 ±1.53, 2.42 ± 1.02, 2.70 ± 1.17 in FGF (1ng ml-1), PDGF (10 ng ml-1) and in combination of FGF and PDGF (1ng ml-1 each) respectively. It can be concluded that PDGF (10 ng ml-1) enhanced cleavage rate and FGF (1ng ml-1) enhanced blastocyst formation rate.

scholarly journals Epigenetic alteration of the donor cells does not recapitulate the reprogramming of DNA methylation in cloned embryos

Reproduction ◽  
2007 ◽  
Vol 134 (6) ◽  
pp. 781-787 ◽  
Author(s):  
Gabbine Wee ◽  
Jung-Jae Shim ◽  
Deog-Bon Koo ◽  
Jung-Il Chae ◽  
Kyung-Kwang Lee ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Trichostatin A ◽  
Dna Methyltransferases ◽  
Epigenetic Reprogramming ◽  
Preimplantation Development ◽  
Developmental Competence ◽  
Epigenetic Mark ◽  
Satellite Sequence ◽  
Donor Cells

Epigenetic reprogramming is a prerequisite process during mammalian development that is aberrant in cloned embryos. However, mechanisms that evolve abnormal epigenetic reprogramming during preimplantation development are unclear. To trace the molecular event of an epigenetic mark such as DNA methylation, bovine fibroblasts were epigeneticallyaltered by treatment with trichostatin A (TSA) and then individually transferred into enucleated bovine oocytes. In the TSA-treated cells, expression levels of histone deacetylases and DNA methyltransferases were reduced, but the expression level of histone acetyltransferases such as Tip60 and histone acetyltransferase 1 (HAT1) did not change compared with normal cells. DNA methylation levels of non-treated (normal) and TSA-treated cells were 64.0 and 48.9% in the satellite I sequence (P < 0.05) respectively, and 71.6 and 61.9% in the α-satellite sequence respectively. DNA methylation levels of nuclear transfer (NT) and TSA-NT blastocysts in the satellite I sequence were 67.2 and 42.2% (P < 0.05) respectively, which was approximately similar to those of normal and TSA-treated cells. In the α-satellite sequence, NT and TSA-NT embryos were substantially demethylated at the blastocyst stage as IVF-derived embryos were demethylated. The in vitro developmental rate (46.6%) of TSA-NT embryos that were individually transferred with TSA-treated cells was higher than that (31.7%) of NT embryos with non-treated cells (P < 0.05). Our findings suggest that the chromatin of a donor cell is unyielding to the reprogramming of DNA methylation during preimplantation development, and that alteration of the epigenetic state of donor cells may improve in vitro developmental competence of cloned embryos.

scholarly journals 240OVINE PREPUBERTAL OOCYTE SHOWS ALTERATE GENE EXPRESSION AND LOW DEVELOPMENTAL COMPETENCE

2004 ◽  
Vol 16 (2) ◽  
pp. 240 ◽  
Author(s):  
G. Leoni ◽  
S. Ledda ◽  
L. Bogliolo ◽  
S. Succu ◽  
I. Rosati ◽  
...  
Keyword(s):  
Gene Expression ◽  
Glucose Transporter ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Hatching Rate ◽  
Cleavage Rate ◽  
Quantitative Expression ◽  
Altered Gene Expression ◽  
Altered Gene

The aim of this work was to evaluate developmental competence and gene expression of prepubertal and adult ovine oocytes. GV prepubertal and adult oocytes were matured, fertilized and cultured in vitro until blastocyst stage;; the time (days) needed to reach this stage was recorded. Blastocysts developed on different days were cultured for hatching to evaluate their quality in relation to cleavage rate. Adult and prepubertal GV oocytes and blastocyst-stage embryos produced, respectively, at 6 and 7 days were compared for quantitative expression of poly(A) polymerase (polyA-P), glucose transporter I (Glut-I), desmocollin II (desmoII), plakofilin (plako) and heat shock protein 70.1 (HSP70) genes. Confirming previous results (Ledda et al., 1996 Zygote 4, 343–348), fertilized prepubertal ovine oocytes developed to blastocyst stage at lower rates than the adult ones (19.9 v. 51.3%, respectively, P&lt;0.001) and this stage was delayed 24h in prepubertal compared to adult embryos (P&lt;0.01), reflecting a lower quality (Fenwick et al., 2002 Hum. Reprod. 17, 407–412) of the former. In fact, 44.7, 25.0, 30.3 and 0% of adult blastocysts were obtained after 6, 7, 8 and 9 days, respectively, of postfertilization culture compared to 0, 48.4, 34.3 and 17.2% of prepubertal ones. Faster-developed blastocysts showed higher hatching rate in both prepubertal (54.8%, 7 days of culture) and adult (89.8%, 6 days). Hatching rate dropped to 18.2% when blastocysts were obtained at 8–9 days in prepubertal and to 54.5% and 32.5% at 7 and 8 days, respectively, in adult embryos. Analysis of gene expression showed that HSP70, plako and desmo genes were not expressed in GV oocytes, and Glut-I mRNA was lower in prepubertal GV oocytes than in the adult ones (P&lt;0.01). All genes were expressed in blastocysts;; we found that Glut-I was at lower levels (P&lt;0.01) in prepubertal-derived blastocysts whereas HSP70 was highly expressed (P&lt;0.05) in prepubertal blastocysts than in those derived from adult oocytes. In conclusion this work shows that prepubertal ovine oocytes have a lower developmental competence compared to the adult ones, correlated to an altered gene expression during the growth phase of the oocyte and early embryonic development. Supported by MIUR (cofin).

165 THE EFFECTS OF L-CARNITINE AND LINOLEIC ACID ALBUMIN SUPPLEMENTATION ON THE DEVELOPMENT AND CRYOSURVIVAL OF BOVINE IN VITRO-MATURED/IN VITRO-FERTILIZED EMBRYOS IN IN VITRO CULTURE MEDIUM

2012 ◽  
Vol 24 (1) ◽  
pp. 194
Author(s):  
S. Miyashita ◽  
Y. Inaba ◽  
T. Somfai ◽  
M. Geshi ◽  
T. Nagai ◽  
...  
Keyword(s):  
Linoleic Acid ◽  
In Vitro Culture ◽  
Culture Medium ◽  
Formation Rate ◽  
Calf Serum ◽  
Developmental Competence ◽  
Control Group ◽  
Blastocyst Formation ◽  
Cleavage Rate

The objective of this study was to investigate the effects of the supplementation of a lipid metabolism inducer, L-carnitine (LC) and a membrane stabilizer, linoleic acid albumin (LAA), on the developmental competence and cryosurvival of bovine in vitro-matured/in vitro-fertilized embryos in in vitro culture medium. Cumulus–oocyte complexes collected from the ovaries of slaughtered cattle were matured for 20 h in TCM-199 supplemented with 5% calf serum (CS) and 0.02 AU mL–1 of FSH at 38.5°C in an atmosphere of 5% CO2 in air. After IVF (Day 0), presumptive zygotes were cultured in CRlaa containing 5% CS at 38.5°C in an atmosphere of 5% CO2, 5% O2 and 90% N2 for 9 days. The culture medium was supplemented with 0.6 mg mL–1 of LC (LC group; n = 180) or with 0.25 mg mL–1 of LAA (LAA group; n = 180) or with both LC and LAA (LC + LAA group; n = 180) or without LC and LAA (control; n = 178). The cleavage rates were recorded on Day 2 and the blastocyst formation rates were recorded on Day 7 to 9. Expanded blastocysts harvested on Day 7 and 8 (LAA group: n = 31; LC group: n = 29; LC + LAA group: n = 25; control group: n = 33) were used for freezing in modified PBS supplemented with 1.5 M ethylene glycol, 0.1 M sucrose and 20% CS. After thawing, they were cultured in TCM-199 supplemented with 20% FBS and 0.1 mM β-mercaptoethanol at 38.5°C under 5% CO2 in air for 72 h. The rates of re-expansion, hatching and formation of hatched blastocysts were determined at 24, 48 and 72 h after thawing, respectively. The rates of cleavage and blastocyst formation were expressed as mean ± s.e.m. and analysed by ANOVA. The post-thaw survival rates of frozen embryos were analysed by chi-square test. The cleavage rate in the control group (69.1 ± 2.5%) was significantly lower than that in the LAA (81.8 ± 3.8%) and LC + LAA groups (77.9 ± 1.4%) but did not differ from that in the LC group (73.8 ± 2.4%). The blastocyst formation rate in the control group (21.7 ± 2.8%) was significantly lower (P < 0.05) than those in the LAA and LC + LAA groups (33.5 ± 2.8% and 31.4 ± 2.4%, respectively), but it did not differ significantly from that of the LC group (32.1 ± 3.3%) despite a strong tendency (P = 0.06). There were no significant differences among the control, LC, LAA and the LC + LAA groups in post-thaw re-expansion rates (66.7, 75.9, 67.7 and 76.0%, respectively), hatching rates (48.5, 69.0, 58.1 and 64.0%, respectively) and rates of formation of hatched blastocysts (51.5, 62.1, 61.3 and 64.0%, respectively). These results indicate that the addition of LC and LAA to the medium for in vitro culture of in vitro-matured/in vitro-fertilized bovine embryos improved their ability to develop to the blastocyst stage; however, the effects on the freezing tolerance were not verified.

82 Invitro embryo production outcomes in adult goats is affected by season

2021 ◽  
Vol 33 (2) ◽  
pp. 149
Author(s):  
P. V. Pereira ◽  
L. Correia ◽  
R. Batista ◽  
V. Freitas ◽  
Y. Locatelli ◽  
...  
Keyword(s):  
Assisted Reproductive Technologies ◽  
Formation Rate ◽  
Calf Serum ◽  
Reproductive Technologies ◽  
Developmental Competence ◽  
Seasonal Effects ◽  
Hatching Rate ◽  
Initial Number ◽  
Cleavage Rate ◽  
Blastocyst Rate

In seasonal breeders, reproductive seasonality can have a substantial influence on the efficiency of assisted reproductive technologies. This study assessed seasonal effects on cleavage and blastocyst rates, as well as on quality of invitro-produced (IVP) goat embryos over 18 months. In total, 2348 (autumn: 811, spring: 404, summer: 639, and, winter: 494) cumulus–oocyte complexes (COC) were recovered from slaughterhouse ovaries during 49 replicates (autumn: 17, spring: 7, summer: 15, and, winter: 10) and matured in TCM-199 with 10ng mL−1 epidermal growth factor and 100µM cysteamine for 22h at 38.8°C (5% CO2 in air). Matured oocytes were fertilized with frozen/thawed semen in synthetic oviductal fluid (SOF) with 10% oestrus sheep serum. Sperm and oocytes were co-incubated for 16h at 38.8°C in a humidified atmosphere of 5% CO2 in air. Presumptive zygotes were cultured in SOF medium supplemented with bovine serum albumin (3mg mL−1) for 8 days at 38.8°C in a humidified atmosphere of 5% O2, 5% CO2 and 90% N2. At Day 2, 10% fetal calf serum was added to the culture droplets. The embryos produced were fixed and stained with Hoechst to count their total number of cells, under an epifluorescence microscope. The results of cleavage and blastocyst rates, including hatching rate, from each routine of IVEP were considered as replicates. These data were tested for normality by the Shapiro-Wilk test, before being subjected to ANOVA, followed by Tukey HSD test. The odds ratio (OR) among seasons (autumn: breeding; spring: anoestrus) were calculated. Values of P&lt;0.05 were considered as significant, and the data reported are mean±s.e.m. Cleavage rate was lower (P&lt;0.05) in spring (51±7.1%) than in either autumn (72±2.1%) or summer (71±2.0%) while winter (66±4.1%) had an intermediate value, being similar (P&gt; 0.05) to all others. Indeed, greater possibility of cleavage was observed in autumn (OR: 2.43) and summer (OR: 2.39) compared with spring. The blastocyst rate from cleaved embryos was greater (P &lt;0.05) in autumn (73±2.7%) than in spring (55±2.6%; OR: 2.18). As a result, the blastocyst formation rate from the initial number of COC entering IVM was greater (P&lt;0.05) in autumn (52±2.5%) than in spring: 28±4.7%, summer: 45±2.3%, and winter: 42±2.1%; indeed, the spring season resulted in the lowest rate (P&lt;0.05), compared with other seasons. Moreover, the OR in the blastocyst rate from initial number of COC was greater (P&lt;0.05) in autumn compared with all other seasons and lower in spring compared with winter (OR: 0.54) and summer (OR: 0.48). There were no differences (P&gt; 0.05) in the embryo hatching (mean: 66±2.0%) and blastocyst cell number (mean: 193±2.0 cells). In conclusion, the breeding season (autumn) leads to improved oocyte developmental competence, resulting in greater cleavage and blastocyst yield, whereas embryo quality remained similar throughout the year. Further studies at the molecular level might indicate the mechanisms involved and provide clues to alleviate the negative effect of season.

Antioxidant β-cryptoxanthin enhances porcine oocyte maturation and subsequent embryo development in vitro

2018 ◽  
Vol 30 (9) ◽  
pp. 1204 ◽  
Author(s):  
Yun-Gwi Park ◽  
Seung-Eun Lee ◽  
Yeo-Jin Son ◽  
Sang-Gi Jeong ◽  
Min-Young Shin ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Polar Body ◽  
Formation Rate ◽  
Cumulus Cells ◽  
Control Group ◽  
Mrna Levels ◽  
Cleavage Rate ◽  
Antioxidant Genes ◽  
Developmental Potential

Oxidative stress is partly responsible for the poor quality of IVM oocytes. The present study investigated the effects of the antioxidant β-cryptoxanthin on the IVM of porcine oocytes and the in vitro development of the ensuing embryos. Oocytes were matured in IVM medium containing different concentrations of β-cryptoxanthin (0, 0.1, 1, 10 or 100 μM). Treatment with 1 µM β-cryptoxanthin (Group 1B) improved polar body extrusion and the expression of maturation-related genes in cumulus cells and oocytes compared with control. In addition, levels of reactive oxygen species decreased significantly in Group 1B, whereas there were significant increases in glutathione levels and expression of the antioxidant genes superoxide dismutase 1 and peroxiredoxin 5 in this group. After parthenogenetic activation, although the cleavage rate did not differ between the control and 1B groups, the blastocyst formation rate was higher in the latter. Moreover, the total number of cells per blastocyst and relative mRNA levels of pluripotency marker and antioxidant genes were significantly higher in the 1B compared with control group. These results demonstrate that β-cryptoxanthin decreases oxidative stress in porcine oocytes and improves their quality and developmental potential.

scholarly journals Reproductive Seasonality Affects In Vitro Embryo Production Outcomes in Adult Goats

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 873
Author(s):  
Joanna M.G. Souza-Fabjan ◽  
Lucas F.L. Correia ◽  
Ribrio I.T.P. Batista ◽  
Yann Locatelli ◽  
Vicente J.F. Freitas ◽  
...  
Keyword(s):  
Breeding Season ◽  
Assisted Reproductive Technologies ◽  
Formation Rate ◽  
Reproductive Technologies ◽  
Cell Number ◽  
Developmental Competence ◽  
Reproductive Seasonality ◽  
Cleavage Rate

Reproductive seasonality may have a considerable influence on the efficiency of assisted reproductive technologies in seasonal species. This study evaluated the effect of season on cleavage, blastocyst rates and quality of in vitro produced (IVP) goat embryos. In total, 2348 cumulus–oocyte complexes (COCs) were recovered from slaughterhouse ovaries and subjected to the same IVP system throughout 1.5 years (49 replicates). The odds ratio (OR) among seasons was calculated from values of cleavage and blastocyst rates in each season. Cleavage rate was lower (p < 0.05) in spring (anestrus), in comparison with either autumn (peak of breeding season) or summer, while the winter had intermediate values. Furthermore, lower OR of cleavage was observed in spring. Blastocyst formation rate (from initial number of COCs) was higher (p < 0.05) in autumn (52 ± 2.5%) when compared with the other seasons (combined rates: 40 ± 1.9%). Moreover, its OR was higher (p < 0.05) in autumn compared to all other seasons and impaired in the spring compared to winter (OR: 0.54) and summer (OR: 0.48). Embryo hatchability and blastocyst cell number were similar (p > 0.05) among seasons. In conclusion, the breeding season leads to improved oocyte developmental competence, resulting in higher cleavage and blastocyst yield, whereas embryo quality remained similar throughout the years.

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

Reproduction ◽  
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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