Effects of ovary storage temperature and embryo vitrification on somatic cell nuclear transfer outcomes in goats

2020 ◽  
Vol 32 (4) ◽  
pp. 419 ◽  
Author(s):  
Mehdi Hajian ◽  
Farnoosh Jafarpour ◽  
Sayed Morteza Aghamiri ◽  
Shiva Rouhollahi Varnosfaderani ◽  
Mohammad Hossein Nasr Esfahani

Improving the genetic potential of farm animals is one of the primary aims in the field of assisted reproduction. In this regard, somatic cell nuclear transfer (SCNT) can be used to produce a large number of embryos from genetically elite animals. The aims of the present study were to assess the effects of: (1) ovary storage conditions on preimplantation development of recovered oocytes and the freezability of the derived blastocysts; and (2) vitrification of goat SCNT-derived blastocysts on postimplantation development. Goat oocytes were recovered from ovaries and stored under warm (25°C-27°C) or cold (11°C-12°C) conditions before being used to produce SCNT embryos. There were no differences in oocytes recovered from ovaries kept under cold versus warm storage conditions in terms of cleavage (mean (±s.d.) 95.68±1.67% vs 95.91±2.93% respectively) and blastocyst formation (10.69±1.17% vs 10.94±0.9% respectively) rates. The re-expansion rate of vitrified blastocysts was significantly lower for cold- than warm-stored ovaries (66.3±8.7% vs 90±11% respectively). To assess the effects of vitrification on postimplantation development, blastocysts from cold-stored ovaries only were transferred from fresh and vitrified–warmed groups. The pregnancy rate was comparable between the fresh and vitrified–warmed groups (41.65% and 45.45% respectively). In addition, established pregnancy in Day 28-38 and full-term pregnancy rates were similar between the two groups. In conclusion, this study shows similar invitro preimplantation developmental potential of warm- and cold-stored ovaries. This study introduces the vitrification technique as an appropriate approach to preserve embryos produced by SCNT for transfer to recipient goats at a suitable time.

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.


2015 ◽  
Vol 27 (1) ◽  
pp. 104
Author(s):  
N. L. Selokar ◽  
M. Saini ◽  
H. Agrawal ◽  
P. Palta ◽  
M. S. Chauhan ◽  
...  

Cryopreservation of semen allows preservation of somatic cells, which can be used for the production of progeny through somatic cell nuclear transfer (SCNT). This approach could enable restoration of valuable high-genetic-merit progeny-tested bulls, which may be dead but the cryopreserved semen is available. We have successfully produced a live buffalo calf by SCNT using somatic cells isolated from >10 year old frozen semen (Selokar et al. 2014 PLoS One 9, e90755). However, the calf survived only for 12 h, which indicates faulty reprogramming of these cells. The present study was, therefore, carried out to study the effect of treatment with trichostatin A (TSA), an epigenetic modifier, on reprogramming of these cells. Production of cloned embryos and determination of quality and level of epigenetic markers in blastocysts were performed according to the methods described previously (Selokar et al. 2014 PLoS One 9, e90755). To examine the effects of TSA (0, 50, and 75 nM), 10 separate experiments were performed on 125, 175, and 207 reconstructed embryos, respectively. The percentage data were analysed using SYSTAT 12.0 (SPSS Inc., Chicago, IL, USA) after arcsine transformation. Differences between means were analysed by one-way ANOVA followed by Fisher's least significant difference test for significance at P < 0.05. When the reconstructed buffalo embryos produced by hand-made clones were treated with 0, 50, or 75 nM TSA post-electrofusion for 10 h, the cleavage percentage (100.0 ± 0, 94.5 ± 2.3, and 96.1 ± 1.2, respectively) and blastocyst percentage (50.6 ± 2.3, 48.4 ± 2.7, and 48.1 ± 2.6, respectively), total cell number (274.9 ± 17.4, 289.1 ± 30.1, and 317.0 ± 24.2, respectively), and apoptotic index (3.4 ± 0.9, 4.5 ± 1.4, and 5.6 ± 0.7, respectively) in Day 8 blastocysts were not significantly different among different groups. The TSA treatment increased (P < 0.05) the global level of H4K5ac but not that of H3K18a in embryos treated with 50 or 75 nM TSA compared with that in controls. In contrast, the level of H3K27me3 was significantly lower (P < 0.05) in cloned embryos treated with 75 nM TSA than in embryos treated with 50 nM TSA or controls. The ultimate test of the reprogramming potential of any donor cell type is its ability to produce live offspring. To examine the in vivo developmental potential of the 0, 50, or 75 nM TSA treated embryos, we transferred Day 8 blastocysts, 2 each to 5, 6, and 5 recipients, respectively, which resulted in 2 pregnancies from 75 nM TSA treated embryos. However, one pregnancy was aborted in the first trimester and the other in the third trimester. In conclusion, TSA treatment of reconstructed embryos produced from semen-derived somatic cells alters their epigenetic status but does not improve the live birth rate. We are currently optimizing an effective strategy to improve the cloning efficiency of semen-derived somatic cells.


2012 ◽  
Vol 24 (1) ◽  
pp. 126
Author(s):  
X. Yang ◽  
J. Mao ◽  
E. M. Walters ◽  
M. T. Zhao ◽  
K. Lee ◽  
...  

Somatic cell nuclear transfer (SCNT) efficiency in pigs and other species is still very low. This low efficiency and the occurrence of developmental abnormalities in offspring has been attributed to incomplete or incorrect reprogramming. Cytoplasmic extracts from both mammalian and amphibian oocytes can alter the epigenetic state of mammalian somatic nuclei as well as gene expression to more resemble that of pluripotent cells. Rathbone et al. (2010) has showed that pretreating somatic donor cells with frog oocyte extract (FOE) increased live birth in ovine. Liu et al. (2011) also reported that treating donor cells with FOE enhanced handmade clone embryo development in pigs. The aim of this study was to evaluate the early development of cloned embryos produced with porcine GFP fibroblasts pre-treated with a permeabilizing agent, digitonin and matured frog oocyte extract. Frog egg cytoplasmic extract was prepared from one frog's oocytes after being matured in vitro to MII stage. The experiment included 2 groups. In the FOE-treated group, GFP-tagged fetal fibroblasts were permeabilized by digitonin (15 ng mL–1) and incubated in FOE containing an ATP-regenerating system (2.5 mM ATP, 125 μM GTP, 62.5 μg mL–1 of creatine kinase, 25 mM phosphocreatine and 1 mM NTP) at room temperature (24°C) for 2 h; cell membranes were re-sealed by culturing in 10% FBS in DMEM media for 2.5 h at 38.5°C before used as donor cells. In the control group, the same donor cells were treated with digitonin, but without frog oocyte extract incubation. The SCNT embryos were produced by using the 2 groups of donor cells as described above. In total, 305 control and 492 FOE oocytes were enucleated from 8 biological replicates. Two hundred fifty control and 370 FOE couplets were fused and cultured in porcine zygote medium 3. Percent cleavage was recorded on Day 2 and the percent blastocyst formation was determined on Day 7 (SCNT day = 0). In addition, the number of nuclei in the blastocysts was recorded on Day 7. Percent fusion, cleavage, blastocyst formation and number of nuclei in blastocysts were analysed by using SAS software (v9.2), with day and treatment class as main effects. There was no difference in percent fusion (FOE, 76.2 ± 2.5% vs control, 80.8 ± 2.8%) or in cleavage (FOE: 74.8 ± 2.5% vs control: 74.6 ± 2.9%). Only green blastocysts with 16 or more nuclei were considered to be a true SCNT blastocyst. The percent blastocyst was higher in the FOE group than that in the control (13.9 ± 0.8% vs 9.5 ± 0.9%, P < 0.05), whereas the number of nuclei in the blastocysts was not different between the 2 groups (39.7 ± 2.4, 35.9 ± 3.8 for FOE and control, respectively). In conclusion, our study demonstrated that pre-treatment of donor cells with digitonin and Xenopus MII oocyte extract increased porcine SCNT embryo development to blastocyst and cloning efficiency. Funded by the National Natural Science Foundation of China (NO. 31071311), Natural Science Foundation of Fujian Province of China (No. 2009J06017) and NIH U42 RR18877.


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.


2020 ◽  
Vol 32 (2) ◽  
pp. 133
Author(s):  
Z.-B. Luo ◽  
M.-F. Xuan ◽  
Z.-Y. Li ◽  
X.-J. Yin ◽  
J.-D. Kang

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). In this study, we compared histone deacetylase inhibitors combined with the pluripotency inducer RepSox on invitro development of porcine embryos produced via SCNT. Porcine embryos were treated with valproic acid (VPA), mocetinostat, M344 and panobinostat (LBH589) after SCNT, respectively. The porcine embryo invitro-development competence, histone modification level, and pluripotency-related genes expression were analysed. The results showed that LBH589 significantly increased the blastocyst formation rate compared with mocetinostat, M344, and control. In addition, VPA treatment increased the blastocyst formation rate of SCNT porcine embryos; both VPA-treated and the untreated clones developed to term, but offspring from VPA-treated embryos had a lower survival to adulthood than those from control embryos (18.2 vs. 67.0%; P&lt;0.05). Furthermore, cotreatment with 12.5mM RepSox and 50 nM LBH589 (RepSox+LBH589) for 24h significantly increased the blastocyst formation rate compared with that of untreated embryos (26.9 vs. 8.5%, respectively; P&lt;0.05). Moreover, RepSox + LBH589 improved epigenetic reprogramming by histone acetylation and methylation. The expression of pluripotency-related genes NANOG and SOX2 was found to be 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. In summary, RepSox + LBH589 increases the expression of developmentally important genes, optimises epigenetic reprogramming, and improves the invitro development of porcine SCNT embryos.


Zygote ◽  
2021 ◽  
pp. 1-8
Author(s):  
Yongjin Lee ◽  
Hanna Lee ◽  
Joohyeong Lee ◽  
Seung Tae Lee ◽  
Geun-Shik Lee ◽  
...  

Summary This study was conducted to examine whether glucose in maturation medium containing reduced NaCl could improve oocyte maturation and embryonic development in pigs. The base medium was bovine serum albumin-free porcine zygote medium (PZM)-3 containing 10% (v/v) pig follicular fluid (FPZM) or 0.1% (w/v) polyvinyl alcohol (PPZM). Using each medium, the effects of NaCl concentrations (108 and 61.6 mM) and 5.56 mM glucose supplementation (designated as PZM108N, PZM108G, PZM61N, and PZM61G, respectively) were examined using a 2 × 2 factorial arrangement. When oocytes were matured in FPZM, glucose supplementation improved nuclear maturation compared with no supplementation, regardless of the NaCl concentrations. FPZM61G showed a higher blastocyst formation compared with FPZM108N and FPZM108G after parthenogenesis (PA). Blastocyst formations of somatic cell nuclear transfer (SCNT) embryos derived from FPZM61N and FPZM61G were higher compared with those of oocytes from FPZM108N. When oocytes were matured in PPZM, glucose added to PPZM108 and PPZM61 increased nuclear maturation compared with no supplementation. However, glucose added to PPZM108 did not alter embryonic development after PA. Additionally, oocytes matured in PPZM61G showed a higher blastocyst formation compared with those from PPZM61N. In SCNT, blastocyst formation was not influenced by glucose supplementation of PPZM108, but was increased by maturation in glucose-supplemented PPZM61. In embryonic development of in vitro fertilization (IVF), oocytes matured in medium with reduced NaCl and glucose showed significantly higher blastocyst formation compared with those matured in PPZM108G. Our results demonstrated that glucose in maturation medium containing 61.6 mM NaCl increased oocyte maturation and embryonic development after PA, SCNT, and IVF.


Author(s):  
Zhenhua Guo ◽  
Lei Lv ◽  
Di Liu ◽  
Zhongqiu Li

Herd boars, male domestic pigs used for stud, are economically important, and somatic cell nuclear transfer (SCNT) is a promising technology to expand herd boar yields. However, live births are dictated by donor cell source, and fetal donors may offer more advantages than adult donors. A meta-analysis was conducted to better understand how donor sources affect SCNT outcomes. Of the 1,431 records viewed, 10 were selected for review. Blastocyst formation rates, successful pregnancies, and live births were assessed to measure efficacy. SCNT blastocyst formation differed between adult and fetal donors among the studies. SCNT pigs had more malformed fetuses as well, which negatively affected the post-birth mortality. Organs of porcine fetuses are limited by deficiencies of maternal nutrient and growth hormones, which compromise post-birth adaptations. SCNT pregnancy success is neither determined by donor source nor by live births. Live births are also tied to donor age. Embryos from fetal donors are more frequently healthy likely due to less differentiation and less reprogramming of reconstructed embryos. Adult donors in contrast have more cell differentiation and as such accumulate more mutations and damage. This may reduce reconstructed embryo viability. Finally, SCNT efficiency may be improved with more in vitro passages, but more work is required to validate this concept.


Zygote ◽  
2008 ◽  
Vol 16 (3) ◽  
pp. 211-222 ◽  
Author(s):  
Wakayama Sayaka ◽  
Kishigami Satoshi ◽  
Nguyen Van Thuan ◽  
Ohta Hiroshi ◽  
Hikichi Takafusa ◽  
...  

SummaryAnimal cloning methods are now well described and are becoming routine. Yet, the frequency at which live cloned offspring are produced remains below 5%, irrespective of the nuclear donor species or cell type. One possible explanation is that the reprogramming factor(s) of each oocyte is insufficient or not properly adapted for the receipt of a somatic cell nucleus, because it is naturally prepared only for the receipt of a gamete. Here, we have increased the oocyte volume by oocyte fusion and examined its subsequent development. We constructed oocytes with volumes two to nine times greater than the normal volume by the electrofusion or mechanical fusion of intact and enucleated oocytes. We examined their in vitro and in vivo developmental potential after parthenogenetic activation, intracytoplasmic sperm injection (ICSI) and somatic cell nuclear transfer (SCNT). When the fused oocytes were activated parthenogenetically, most developed to morulae or blastocysts, regardless of their original size. Diploid fused oocytes were fertilized by ICSI and developed normally and after embryo transfer, we obtained 12 (4–15%) healthy and fertile offspring. However, enucleated fused oocytes could not support the development of mice cloned by SCNT. These results suggest that double fused oocytes have normal potential for development after fertilization, but oocytes with extra cytoplasm do not have enhanced reprogramming potential.


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