scholarly journals Effects of 6-dimethylaminopurine, cytochalasin B and cycloheximide on in vitro development of I pig cloned embryos

2020 ◽  
Vol 18 (3) ◽  
pp. 455-463
Author(s):  
Nguyen Khanh Van ◽  
Quan Xuan Huu ◽  
Vu Thi Thu Huong ◽  
Pham Doan Lan

The present study was conducted to evaluate the effects of 6-dimethylaminopurine (6-DMAP), cytochalasin B (CyB) and cycloheximide (CHX) on in vitro development of “I” pig somatic cell nuclear transfer embryos. Oocytes after SCNT were activated with 2 mM 6-DMAP; 7.5 µg/ml CyB and 10 µg/ml CHX. The results indicated that the rate of oocytes no lysis in group activated by CHX was significantly lower compared with those in group activated by 6-DAMP and CyB (90.91% and 88.01%, respectively, P < 0,05). The blastocyst formation rate did not differ between group actvated by 6-DAMP and CyB (24.93% vs 24.4%, P > 0.05). Meanwhile the blastocyst formation rate in group activated by CHX was 15.01%, significantly lower than that in group activated by 6-DAMP and CyB (P < 0.05). The average number of cells in the blastocyst in group activated by 6-DAMP and CyB were higher than that in group activated by CHX (47.78, 44.57 vs 39.42, respectively). The use of 6-DMAP and CyB in the activation of pig oocytes after SCNT was more effective than CHX. The results of this study show that for the first time in Vietnam, we have created “I” pig SCNT embryo without zona pellucida with the rate of blastocyst formation from 15.01% to 24.93%.

2017 ◽  
Vol 29 (1) ◽  
pp. 125
Author(s):  
G. V. Landschoot ◽  
V. Savy ◽  
N. Canel ◽  
S. Ferraris ◽  
D. Salamone

Cloning of domestic species by somatic cell nuclear transfer (SCNT) continues to be inefficient, probably due to an incomplete reprogramming of the reconstituted embryo. The ability of the embryonic cytoplasm to support reprogramming fluctuates within the cell cycle (Egli et al. 2007 Nature 447, 679–85). In this context, we compared the development capability and second polar body (2PB) extrusion of embryos produced by metaphase (M) cells, in comparison with G0/G1 cells, which are commonly used as nuclear donors. Because M cells have 2 sets of chromosomes (in contrast with G0/G1 cells, which have only 1 set), an activation protocol that impedes 2PB extrusion is required to produce reconstituted embryos with the correct ploidy. Therefore, we performed SCNT with M or G0/G1 cells, followed by different activation protocols, and evaluated in vitro development and 2PB extrusion of the reconstituted embryos. Cow oocytes were in vitro matured and enucleated as described by Gambini et al. (2014 PLoS One 14, 9). A group of cells at 70 to 80% confluence was synchronized in M stage using 0.05 μg mL−1 demecolcine for 3 to 4 h and used as nuclear donors for SCNT (M group). Another group of cells was induced into quiescence by serum starvation for 3 to 4 days before SCNT (G0/G1 group). For activation, reconstituted embryos were treated with 5 µM ionomycin (Io) for 4 min followed by 5-h incubation in 50 μM roscovitine for M group, or in 50 μM roscovitine and 5 μg mL−1 cytochalasin B for G0/G1 group. Parthenogenetic controls were activated with Io followed by 50 μM roscovitine alone (ROSCO) or with 5 μg mL−1 cytochalasin B (ROSCO/CB). Hoescht 33342 staining was performed 16 h post-Io to evaluate 2PB extrusion. Other activated oocytes were cultured in SOFaa medium and rates of cleavage, morulas, and blastocysts were evaluated at Days 2, 5 and 7 of in vitro development, respectively. Data were analysed by Fisher’s exact test (P < 0.05). Rates of 2PB extrusion were 72.72 (n = 33), 65.63 (n = 32), 80 (n = 15), and 42.86 (n = 14) for M, G0/G1, ROSCO, and ROSCO/CB, respectively. Results of in vitro development are shown in Table 1. In conclusion, somatic M cells can be used as donors to produce cloned embryos. The M and G0/G1 groups were able to induce cloned blastocysts, even though rates did not differed statistically from controls groups (ROSCO and ROSCO/CB). The M group was as effective as G0/G1. Although further analysis is required to establish the quality of the embryos, our results are encouraging for use in SCNT. Table 1.In vitro development of NT embryos produced with M and G0/G1 donor cells


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.


2007 ◽  
Vol 19 (1) ◽  
pp. 262
Author(s):  
W. Fujii ◽  
H. Funahashi

If diploid zygotes constituted with a somatic and a maternal genome could successfully develop to term, a new reproductive method would be developed to produce animals. However, there appears to be little information on this subject. In the present study, in vitro early development of the constituted zygotes was examined. A cumulus cell was microinjected into a rat non-enucleated oocyte, the reconstructed oocyte was chemically activated, and the pronuclear formation and in vitro development of the embryo was observed. Prepubertal Wistar female rats (21–27 days old) were induced to superovulate with an IP injection of 15 IU of eCG, followed by 15 IU of hCG 48 h later. Cumulus cells were removed from oocytes by pipetting with 0.1% hyaluronidase. Experiment 1: The DNA content of cumulus cells for microinjection was evaluated by flow cytometry. Experiment 2: The optimal concentration of SrCl2 for activation of rat oocytes was examined. Experiment 3: Cumulus cells were injected into mature oocytes in BSA-free HEPES-buffered mKRB containing 0.1% polyvinyl alcohol (PVA) and cytochalasin B (5 �g mL-1), and were then chemically activated by treatment in Ca2+-free mKRB containing 5 mM SrCl2 for 20 min at 0 to 0.5 (A), 1 to 1.5 (B), or 3 to 3.5 h (C) after injection. Activated embryos were cultured in droplets of mKRB in an atmosphere of 5% CO2 in air at 37�C for 9 to 12 h. After being observed for pronuclear formation, the embryos were transferred into mR1ECM-PVA, and the cleavage and blastocyst formation rates were examined 24 and 120 h later, respectively. Results from 3 to 7 replicates were analyzed by ANOVA and Duncan's multiple range test. A total of 90.0 and 9.5% of cumulus cells derived from ovulated oocyte–cumulus complexes contained 2C and 4C DNA contents, respectively. Survival rates did not differ among oocytes stimulated with 0 to 5 mM SrCl2 (96.7–100%) but did differ between those stimulated with 1.25 and 10 mM SrCl2 (100 and 72.9%, respectively). Activation rates of oocytes increased at higher SrCl2 concentrations and were higher at 5 and 10 mM (92.6 and 98.5%, respectively) than at other concentrations. When cumulus-injected oocytes were activated after various periods after the injection, the incidences of pronuclear formation and cleavage did not differ among the periods (A: 95.0 and 81.3%; B: 85.6 and 85.0%; and C: 82.7 and 84.6%, respectively). Although a majority of the embryos developed to the 2- to 4-cell stages (78.7%; 152/208), the blastocyst formation rate was very low (0.8%; 2/208). In conclusion, rat non-enucleated oocytes injected with a cumulus cell can form pronuclei and cleave following chemical activation, but blastocyst formation of the embryos is very limited.


2010 ◽  
Vol 22 (1) ◽  
pp. 190
Author(s):  
Y. J. Kim ◽  
K. S. Ahn ◽  
M. J. Kim ◽  
H. Shim

Epigenetic modification influences reprogramming and subsequent development of somatic cell nuclear transfer embryos. Such modification includes an increase of histone acetylation and a decrease of DNA methylation in transferred donor nuclei. Histone deacetylase inhibitors (HDACi) such as trichostatin A (TSA) and valproic acid (VPA) have been known to maintain high cellular levels of histone acetylation. Hence, the treatment of HDACi to NT embryos may increase efficiency of cloning. Indeed, TSA treatment has significantly enhanced the developmental competence of nuclear transfer embryos in several species including pigs (Zhang et al. 2007 Cloning Stem Cells 9, 357-363; Li et al. 2008 Theriogenology 70, 800-808). Valproic acid, another type of HDACi, has often been used to assist reprogramming of somatic cells into induced pluripotent stem cells in mice. In the present study, we tested the potency of VPA compared with TSA on the enhancement of in vitro development in porcine nuclear transfer embryos. Reconstructed embryos were produced by transferring nuclei of adult ear skin fibroblasts into enucleated oocytes. After electrical activation, these embryos were cultured in PZM-3 containing no HDACi (control), 5 mM VPA, or 50 nM TSA for 24 h, and another 5 days thereafter without HDACi. At least 3 replicates were conducted for the following experiments. The rates of cleavage were not different among the VPA, TSA, and control groups. However, the rate of blastocyst development was significantly higher (P < 0.05) in embryos treated with VPA than in those treated with TSA and without HDACi (125/306, 40.8% v. 94/313, 30.0% v. 80/329, 24.3%). Differential staining of inner cell mass (ICM) and trophectoderm (TE) also supported the beneficial effect of VPA treatment in NT embryos. Compared with the control group, the number of TE cells was significantly increased (P < 0.05) in the VPA and TSA treatment groups (79.3 ± 7.4 v. 74.6 ± 9.2 v. 40.0 ± 6.7). Moreover, VPA treatment significantly increased (P < 0.05) the number of ICM cells compared with the control (15.6 ± 1.7 v. 10.8 ± 2.6), whereas no differences were observed between the TSA treatment and control group (12.9 ± 3.0 v. 10.8 ± 2.6). The present study demonstrates that VPA enhances in vitro development of nuclear transfer embryos, in particular by an increase of blastocyst formation and the number of ICM cells, suggesting that VPA may be more potent than TSA in supporting developmental competence of cloned embryos. However, long-term effects of different HDACi in the development of nuclear transfer embryos, including any adverse outcome from destabilizing epigenetic condition, remain to be determined by further in vivo embryo transfer studies.


2017 ◽  
Author(s):  
◽  
Bethany Rae Mordhorst

Gene edited pigs serve as excellent models for biomedicine and agriculture. Currently, the most efficient way to make a reliably-edited transgenic animal is through somatic cell nuclear transfer (SCNT) also known as cloning. This process involves using cells from a donor (which may have been gene edited) that are typically grown in culture and using their nuclear content to reconstruct a new zygote. To do this, the cell may be placed in the perivitelline space of an enucleated oocyte and activated artificially by a calcium-containing media and electrical pulse waves. While it is remarkable that this process works, it is highly inefficient. In pigs the success of transferred embryos becoming live born piglets is only 1-3%. The creation of more cloned pigs enables further study for the benefit of both A) biomedicine in the development of prognosis and treatments and B) agriculture, whether it be for disease resistance, feed efficiency, gas emissions, etc. Two decades of research has not drastically improved the cloning efficiency of most mammals. One of the main impediments to successful cloning is thought to be due to inefficient nuclear reprogramming and remodeling of the donor cell nucleus. In the following chapters we detail our efforts to improve nuclear reprogramming of porcine fetal fibroblasts by altering the metabolism to be more blastomere-like in nature. We used two methods to alter metabolism 1) pharmaceutical agents and 2) hypoxia. After treating donor cells both methods were used in nuclear transfer. Pharmaceutical agents did not improve in vitro development of gestational survival of clones. Hypoxia did improve in vitro development and we are currently awaiting results of gestation.


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