332 EMBRYONIC DEVELOPMENT AFTER SOMATIC CELL NUCLEAR TRANSFER OF PORCINE OOCYTES MEIOTICALLY INHIBITED WITH ROSCOVITINE

2006 ◽  
Vol 18 (2) ◽  
pp. 273
Author(s):  
S. W. Kim ◽  
D. H. Kim ◽  
J. S. Seo ◽  
G. S. Im ◽  
B. C. Yang ◽  
...  

Numerous factors affect on the developmental competence of cloned embryos, and one of the factors might be the disturbed synchronization of nuclear and cytoplasm maturation. Roscovitine, a purine known to specifically inhibit M-phase promoting factor (MPF) kinase activity by blocking the ATP in numerous cell systems, has been successfully used in maintaining porcine oocytes at GV stage without affecting their developmental potential. However, developmental ability of roscovitine treated porcine oocytes after nuclear transfer has not been evaluated. The purpose of this study was to examine the development of nuclear transferred porcine embryos after meiotic inhibition with roscovitine (ROS). Cumulus-oocyte complexes (COCs) were collected from antral follicles of slaughtered prepubertal gilts. COCs were cultured in pre-maturation medium (TCM-199 containing 50 �M Roscovitine) for 24 h, and then further cultured in conventional maturation medium for 44 h. A control group was cultured in the maturation medium for 44 h. Matured oocytes were enucleated and a porcine fetus cell was inserted into each enucleated oocyte. Couplets were simultaneously fused and activated with electric pulse of two 1.2 kV/cm for 30 �s. Nuclear transferred (NT) embryos were cultured in PZM-1 medium for 6 days (five replicates). Apoptotic cell death was analyzed by using a TUNEL assay and total cell number was examined by Hoechest 33342 counterstaining. At 3 h after fusion, NT embryos were fixed for microfilament staining. Data were analyzed by ANOVA and Student's t-test. The rates of fusion, cleavage, and blastocyst formation of the ROS-treated group (85, 68, and 18%, respectively) after nuclear transfer did not differ from control (78, 76, and 16%, respectively). The cell number in blastocysts of the ROS-treated group (30.8 � 10.6) was significantly lower than that of the control (42.3 � 13.7) (P < 0.01), but the mean proportion of apoptotic cells was not different between the two groups (6.9 � 7.1 and 4.8 � 4.9% for control and ROS group, respectively). Recovery of microfilaments after fusion was delayed in NT embryos derived from ROS-treated oocytes. This study demonstrated that porcine oocytes pre-cultured for 24 h in presence of roscovitine can be developed to blastocysts after somatic cell nuclear transfer. This could provide flexibility for studying porcine oocyte development and embryo cloning.

2018 ◽  
Vol 30 (10) ◽  
pp. 1342 ◽  
Author(s):  
Zhao-Bo Luo ◽  
Long Jin ◽  
Qing Guo ◽  
Jun-Xia Wang ◽  
Xiao-Xu Xing ◽  
...  

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.


2018 ◽  
Vol 30 (1) ◽  
pp. 155
Author(s):  
W.-J. Zhou ◽  
S. Liang ◽  
X.-S. Cui

MicroRNAs (miRNAs) are small non-coding RNAs with important roles in diverse cellular processes. miR-29b plays a crucial role during somatic cell reprogramming. However, studies of the function of miR-29b in embryogenesis are limited. The aim of the current study was to explore the effects of miR-29b on the developmental competence of bovine somatic cell nuclear transfer (SCNT) embryos as well as the underlying mechanisms of action. The expression level of miR-29b was lower in bovine SCNT embryos at the pronuclear, 8-cell, and blastocyst stages compared with IVF embryos (P < 0.05). To determine the function of miR-29b in the bovine SCNT embryo, we microinjected a miR-29b mimic and inhibitor into bovine SCNT zygotes. The results showed that miR-29b significantly decreased the expression of Dnmts (Dnmt3a/3b and Dnmt1) in bovine SCNT embryos (P < 0.05). We further investigated SCNT embryo developmental competence and found that miR-29b overexpression during bovine SCNT embryonic development does not improve developmental potency (P > 0.05) but down-regulation inhibits developmental potency (P < 0.05). Although miR-29b overexpression does not improve the developmental potency of bovine SCNT embryos, the quality of bovine SCNT embryos at the blastocyst stage improved significantly (P < 0.05). The expression of pluripotency factors (OCT4 and SOX2) and cellular proliferation rate were significantly higher in blastocysts from the miR-29b overexpression group than the control and down-regulation groups (P < 0.05). In addition, outgrowth potential in blastocysts after miR-29b overexpression was also significantly greater in the miR-29b overexpression group than in the control and down-regulation groups (P < 0.05). Taken together, these results demonstrated that miR-29b plays an important role in bovine SCNT embryo development.


2015 ◽  
Vol 27 (3) ◽  
pp. 544 ◽  
Author(s):  
H. S. Pedersen ◽  
Y. Liu ◽  
R. Li ◽  
S. Purup ◽  
P. Løvendahl ◽  
...  

Pig oocytes have been used increasingly for in vitro production techniques in recent years. The slaughterhouse-derived oocytes that are often used are mostly of prepubertal origin. The aims of the present study were to compare the developmental competence between pre- and postpubertal pig oocytes, and to develop a simple and practical method for the selection of prepubertal pig oocytes for parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) based on oocyte morphology after IVM and oocyte inside zona pellucida (ZP) diameter (‘small’ ≤110 µm; ‘medium’ >110 µm; ‘large’ ≥120 µm). Meiotic competence and blastocyst rates after PA and SCNT of prepubertal oocytes increased with oocyte size, with the large prepubertal oocytes reaching a level similar to postpubertal oocytes after SCNT. Blastocyst cell number was not related to oocyte inside ZP diameter and oocyte donor to the same extent as blastocyst rate. Very low blastocyst rates were obtained after PA of morphologically bad pre- and postpubertal oocytes. In conclusion, measurement of inside ZP diameter combined with morphological selection is useful to remove incompetent oocytes. Further studies are needed to clarify the relative importance of cytoplasmic volume and stage in oocyte growth phase.


2003 ◽  
Vol 15 (3) ◽  
pp. 179 ◽  
Author(s):  
Goo Jang ◽  
Byeong Chun Lee ◽  
Sung Keun Kang ◽  
Woo Suk Hwang

The purpose of this study was to evaluate the effect of glycosaminoglycans (GAGs) added to the culture medium on the developmental competence of bovine embryos derived from in vitro fertilization (IVF) and from somatic cell nuclear transfer (SCNT). In vitro-matured oocytes were either inseminated with 1 × 106 spermatozoa mL−1 or enucleated and reconstructed with bovine adult ear fibroblasts by SCNT. The embryos were then cultured in modified synthetic oviduct fluid (mSOF) containing 8 mg mL−1 bovine serum albumin (BSA) (control mSOF) or control mSOF supplemented with various GAGs (hyaluronic acid, heparin or chondroitin sulfate) in a dose-dependent manner (0.1, 0.5 or 1.0 mg mL−1). Developmental competence was evaluated by monitoring the numbers of 2-cell embryos, 8–16-cell embryos and blastocysts. The mean cell number of flattened blastocysts stained with 5 μ M bisbenzimide on Day 8 was counted. The percentage of blastocyst formation (IVF and SCNT embryos) from cleaved embryos was significantly higher (P < 0.05) in control mSOF supplemented with 0.5 mg mL−1 hyaluronic acid (45% and 47%), heparin (40% and 47%) or chondroitin sulfate (38% and 44%) compared with control mSOF (30–31% and 30–33%). When compared with the efficacy of 0.5 mg mL−1 GAGs, no significant differences were observed in the developmental competence of both IVF and SCNT embryos. Supplementing control mSOF with 0.5 mg mL−1 GAGs had no effect on the cell number of IVF embryos. In contrast, supplementing 0.5 mg mL−1 of hyaluronic acid, heparin or chondroitin sulfate to control mSOF significantly (P < 0.05) increased the numbers of total cells (93–98 v. 88 cells) and trophectoderm (TE) cells (64–66 v. 55 cells), and decreased the inner cell mass (ICM) to TE cell ratio (48.2–49.8 v. 61.3) in SCNT blastocysts compared with embryos in control mSOF. In conclusion, supplementation of culture media with GAGs may improve the development of bovine IVM–IVF and SCNT embryos to the blastocyst stage. The GAGs increased the quality of blastocysts by increasing total cell numbers in the SCNT embryos.


Author(s):  
Pil-Soo Jeong ◽  
Hae-Jun Yang ◽  
Soo-Hyun Park ◽  
Min Ah Gwon ◽  
Ye Eun Joo ◽  
...  

Developmental defects in somatic cell nuclear transfer (SCNT) embryos are principally attributable to incomplete epigenetic reprogramming. Small-molecule inhibitors such as histone methyltransferase inhibitors (HMTi) and histone deacetylase inhibitors (HDACi) have been used to improve reprogramming efficiency of SCNT embryos. However, their possible synergistic effect on epigenetic reprogramming has not been studied. In this study, we explored whether combined treatment with an HMTi (chaetocin) and an HDACi (trichostatin A; TSA) synergistically enhanced epigenetic reprogramming and the developmental competence of porcine SCNT embryos. Chaetocin, TSA, and the combination significantly increased the cleavage and blastocyst formation rate, hatching/hatched blastocyst rate, and cell numbers and survival rate compared to control embryos. In particular, the combined treatment improved the rate of development to blastocysts more so than chaetocin or TSA alone. TSA and combined chaetocin/TSA significantly reduced the H3K9me3 levels and increased the H3K9ac levels in SCNT embryos, although chaetocin alone significantly reduced only the H3K9me3 levels. Moreover, these inhibitors also decreased global DNA methylation in SCNT embryos. In addition, the expression of zygotic genome activation- and imprinting-related genes was increased by chaetocin or TSA, and more so by the combination, to levels similar to those of in vitro-fertilized embryos. These results suggest that combined chaetocin/TSA have synergistic effects on improving the developmental competences by regulating epigenetic reprogramming and correcting developmental potential-related gene expression in porcine SCNT embryos. Therefore, these strategies may contribute to the generation of transgenic pigs for biomedical research.


2018 ◽  
Vol 30 (1) ◽  
pp. 158
Author(s):  
L. Xu ◽  
M.-D. Joo ◽  
A. Mesalam ◽  
S.-H. Song ◽  
S. Zhang ◽  
...  

Bovine somatic cell nuclear transfer (SCNT) embryos can develop to the blastocyst stage at a rate similar to that of embryos produced by IVF; however, its efficiency remains low. In this study, we examined the effects of cytoplasm restoration of enucleated oocyte, by injecting ~30% of the cytoplasm of a donor oocyte to restore the enucleated oocyte cytoplasm volume to normal, on the developmental competence and quality of bovine cloned embryos during pre-implantation using the TUNEL assay, quantitative reverse transcription PCR (RT-qPCR) and immunocytochemistry. The experiment was conducted in 6 replicates. The differences in embryo development and expression levels of the various genes between experimental groups were analysed by one-way ANOVA. The level of statistical significance was set at P < 0.05. The percentages of embryos that underwent cleavage and formed a blastocyst were significantly higher (P < 0.05) in the cytoplasmic injected group than in the traditional SCNT group (61.5 ± 1.3% v. 39.7 ± 2.1% and 28.9 ± 0.8% v. 20.2 ± 1.3%, respectively). Furthermore, the beneficial effects of cytoplasmic injection on the cloned embryos were associated with a significantly increased (P < 0.05) total cell number in Day 8 blastocysts compared with the traditional SCNT group (176.2 ± 6.5 v. 119.3 ± 7.7; P < 0.05); however, there was no difference (P > 0.05) between the number of apoptotic cells per blastocyst in the cytoplasmic injected group and in the traditional SCNT group (3.5 ± 1.1 v. 4.1 ± 0.8). Moreover, cytoplasm restoration of enucleated oocyte significantly increased (P < 0.05) mitochondrial activity, as identified by MitoTracker Green (Thermo Fisher Scientific, Waltham, MA, USA). Reverse transcription-qPCR showed that the mRNA levels of DNA methyl-transferase 1 and DNA methyl-transferase 3a were significantly decreased (P < 0.05) in cytoplasmic injected group compared with the traditional SCNT group, but did not significantly differ (P > 0.05) between the cytoplasmic injected and IVF groups. Taken together, these data suggest that cytoplasm restoration of enucleated oocyte improves in vitro developmental competence and quality of bovine cloned embryos, as evidenced by increased total cell numbers, reprogramming efficiency, and mitochondria activity. This work was partly supported by grant from the Next-Generation BioGreen21 (No. PJ01107703), IPET (No. 315017-5 and 117029-3), Allergy free cat (Co. Felix Pets) and BK21plus.


Zygote ◽  
2013 ◽  
Vol 22 (2) ◽  
pp. 213-217 ◽  
Author(s):  
Mohammad Salehi ◽  
Yoko Kato ◽  
Yukio Tsunoda

SummaryThe beneficial effect of supplementing culture medium with melatonin has been reported during in vitro embryo development of species such as mouse, bovine and porcine. However, the effect of melatonin on mouse somatic cell nuclear transfer remains unknown. In this study, we assessed the effects of various concentrations of melatonin (10−6 to 10−12 M) on the in vitro development of mouse somatic cell nuclear transfer embryos for 96 h. Embryos cultured without melatonin were used as control. There was no significant difference in cleavage rates between the groups supplemented with melatonin, dimethyl sulphoxide (DMSO) and the control. The rate of development to blastocyst stage was significantly higher in the group supplemented with 10−12 M melatonin compared with the control group (P < 0.05). Thus, our data demonstrated that adding melatonin to pre-implantation mouse nuclear-transferred embryos can accelerate blastocyst formation.


2020 ◽  
Vol 32 (5) ◽  
pp. 508
Author(s):  
S. Sah ◽  
A. K. Sharma ◽  
S. K. Singla ◽  
M. K. Singh ◽  
M. S. Chauhan ◽  
...  

Expression levels of 13 microRNAs (miRNAs) were compared between buffalo blastocysts produced by somatic cell nuclear transfer through hand-made cloning and IVF to improve cloning efficiency. Expression of miR-22, miR-145, miR-374a and miR-30c was higher, whereas that of miR-29b, miR-101, miR-302b, miR-34a, miR-21 and miR-25 was lower, in nuclear transferred (NT) than IVF embryos; the expression of miR-200b, miR-26a and miR-128 was similar between the two groups. Based on these, miR-145, which is involved in the regulation of pluripotency, was selected for further investigation of NT embryos. miR-145 expression was lowest at the 2-cell stage, increased through the 4-cell stage and was highest at the 8-cell or morula stage in a pattern that was similar between NT and IVF embryos. miR-145 expression was higher in NT than IVF embryos at all stages examined. Treatment of reconstructed embryos 1h after electrofusion with an inhibitor of miR-145 for 1h decreased the apoptotic index and increased the blastocyst rate, total cell number, ratio of cells in the inner cell mass to trophectoderm, global levels of acetylation of histone 3 at lysine 18 and expression of Krueppel-like factor 4 (KLF4), octamer-binding transcription factor 4 (OCT4) and SRY (sex determining region Y)-box 2 (SOX2) in blastocysts. Treatment with an miR-145 mimic had the opposite effects. In conclusion, treatment of NT embryos with an miR-145 inhibitor improves the developmental competence and quality, and increases histone acetylation and expression of pluripotency-related genes.


2010 ◽  
Vol 55 (No. 7) ◽  
pp. 267-275
Author(s):  
S. Hua ◽  
J. Lan ◽  
Y.G. Liu ◽  
Y.L. Song ◽  
J. Liu ◽  
...  

To improve the culture system of bovine somatic cell nuclear transfer (SCNT) embryos, we studied the effects of activin A on developmental competence of bovine SCNT embryos during the early development stage based on the traditional culture method, and analyzed the expression level of the genes related to blastocyst hatching (Na/K-ATPase, Glut-1) and related to activin A signalling pathway (ActRII and Smad2). We generated the bovine SCNT embryo using a Holstein cow oocyte as recipient cytoplasm and a foetal ear fibroblast (Holstein cow, 120 days) as donor cell. The embryos were cultured as follows: experiment 1, the addition of activin A at the concentrations of 0 (control), 20 (M1&ndash;20), 40 (M1&ndash;40) or 80 ng/ml (M1&ndash;80) to the media during the first three days and no addition during the subsequent 5 days; experiment 2, no addition of activin A to the media during the first 3 days and the addition of activin A at the concentrations of 0 (control), 20 (M2&ndash;20), 40 (M2&ndash;40) or 80 ng/ml (M2&ndash;80) during the subsequent 5 days. The results indicated that the blastocyst formation rate and hatching rate, and total blastomere numbers as well as ICM/TE obtained in experiment 1 were not significantly different from the control group (P &gt; 0.05). In contrast, these values obtained in experiment 2 were significantly higher than in the control group (P &lt; 0.05). In addition, the relative abundance (ratio to GAPDH mRNA) of each gene (Glut-1, ActR II and Smad2) was not significantly different among the treatments in the experiment. The expression levels of 4 genes (Na/K-ATPase, Glut-1, ActR II and Smad2) in blastocysts obtained in experiment 2 were higher than those obtained in experiment 1. In conclusion, the present study suggests that the addition of activin A to the culture media from day 4 to day 8 can enhance the developmental competence of bovine SCNT embryos.


2016 ◽  
Vol 28 (9) ◽  
pp. 1360 ◽  
Author(s):  
L. Antonio González-Grajales ◽  
Laura A. Favetta ◽  
W. Allan King ◽  
Gabriela F. Mastromonaco

Altered communication between nuclear and cytoplasmic components has been linked to impaired development in interspecies somatic cell nuclear transfer (iSCNT) embryos as a result of genetic divergence between the two species. This study investigated the developmental potential and mitochondrial function of cattle (Bos taurus), plains bison (Bison bison bison) and wood bison (Bison bison athabascae) embryos produced by iSCNT using domestic cattle oocytes as cytoplasts. Embryos in all groups were analysed for development, accumulation of ATP, apoptosis and gene expression of nuclear- and mitochondrial-encoded genes at the 8–16-cell stage. The results of this study showed no significant differences in the proportion of developed embryos at the 2-, 4- and 8–16-cell stages between groups. However, significantly higher ATP levels were observed in cattle SCNT embryos compared with bison iSCNT embryos. Significantly more condensed and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL)-positive nuclei were found in plains bison iSCNT embryos. No significant differences in the expression levels of nuclear respiratory factor 2 (NRF2) or mitochondrial subunit 2 of cytochrome c oxidase (mt-COX2) were found in any of the groups. However, mitochondrial transcription factor A (TFAM) expression significantly differed between groups. The results of this study provide insights into the potential causes that might lead to embryonic arrest in bison iSCNT embryos, including mitochondrial dysfunction, increased apoptosis and abnormal gene expression.


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