• Journal of Embryo Transfer
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• v.12 no.3
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• pp.335-341
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• 1997

The aims of this study are to establish a stable isolation method of blastomeres from bovine early embryos and examine their developmental potential in vitro Early embryos were produced by maturation and fertilizaion in vitro of bovine follicular oocytes. Blastomeres were isolated from 2~8-cell embryos in $Ca^2$+-, $Mg^2$+-free PBS+EDTA after removing the zonae pellucidae Isolated blastomeres were cultured in CZB containing BOEC for upto 240 hpi. Cleavage rates of them were 18.5%(10 /54) in 1 /2 blastomeres, 33.3%(16/48) in 1/4 blastomeres and 34.2%(14 /41) in 1/8 blastomeres, respectively. The rates of blastocystic vesicle formed were 8.7%(4 /46) in 1/2 blastomeres, 26.6% (17/64) in 1/4 blastomeres and 10.3%(8 /78) in 1/8 blastomeres, respectively. Blastomeres developed into various types of blastocystic vesicles and trophoblastic vesicles as evidenced by the Hoechst 33258 staining and morphology. This results suggest that the isolation method used and subsequent culture of isolated blastomeres from bovine early embryos should be useful to obtain extra embryonic cells for various analyses such as PCR and putative ES cell culture.

• Korean Journal of Animal Reproduction
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• v.7 no.1
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• pp.24-29
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• 1983

These experiments were carried out to obtain basic information necessary of the success of in vitro culture of blastomeres separated from mouse embryo. Total 446 single blastomeres separated from 2-, 4- and 8-cell mouse embryos by protease treatment (0.5% in Whittingham's medium), were cultured under the gas phase of 5% CO2 in air at 37$^{\circ}C$. whittingham's medium was used for culture of blastomeres. The results obtained in these experiments were summerized as follows: 1. Of total 446 blastomeres cultured, 127(87.0%), 134(73.2%) and 77(65.8%) blastomeres separated repectively from 2-, 4- and 8-cell embryos were developed to morula or blastular stages. 2. The numbers of blastomeres, being separated from 2-. 4- and 8-cell embryos and developing to blastocysts containing inner cell mass, were 97(76.4%), 86(64.2%) and 33(42.9%) respectively. 3. After in vitro culture of the blastomeres, the incidence of trophoblastic vesicles increased with the development of the cell stage of embryo. In case of blastomeres separated from 8-cell embryos, 50.6% of blastomeres that developed to blastular stage was trophoblastic vesicles.

• The Korean Journal of Zoology
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• v.30 no.3
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• pp.248-260
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• 1987

In order to investigate the importance of the prospective mesodermal and endodermal blastomeres at 32-cell stage in the anis formation, blastomeres were deleted or transplanted into the ventrovegital site of another normal embryo. The results are as follows: When the dorsomesodermal or dorsoendodermal blastomeres were deleted, there was a substantial developmental lesion in the axis structure. However, when the ventromesodermal or ventroendodermal blastomeres were deleted, the formation of an axis structure was nearly normal. The dorsomesodermal or dorsoendodermal blastomeres which were transplanted into the ventral side of the normal 32-cell embryo caused the formation of a secondary body axis, and the capacity of the second axis induction in the dorsomesodermal blastomeres was a little higher than that in the dorsoendodermal blastomeres. These results imply that both the dorsomesodermal and dorsoendodermal blastomeres are involved in the formation of a set of dorsal body structures during early embryogenesis. As well, in order to investigate the axis inducing capacity in the early cleavage embryos, the dorsovegital blastomeres were transplanted into the ventrovegital site at 4-cell, 8-cell and 16-ceIL stage respectively. As a ruts·fIt, a second body axis was formed. Therefore, it seems that the early cleavage embryo as 4-cell stage dorsal blastomeres contain some informations necessary for the axis formation.

• Korean Journal of Animal Reproduction
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• v.16 no.4
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• pp.341-346
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• 1993

The development of isolated blastomeres from mammalian preimplantation embryos has been basically studied for the multiplication of embryos from superior animals. Therefore, this study was investigated the effect of co-culture with mouse fetal fibroblast cells(MFFC) on in vitro development of blastomeres from mouse preimplantation embryos. Mature female ICR mice were treated with hormone to induce superovulation and embryos were collected at each 2, 4, and 8-cell stage. Then, after removing zona pellucida with protease, blastomeres were isolated by micropipetting, or reconstituted with different stage blastomere, and incubated for 72 hrs either in T6 or TCM199 or on the monolayer of MFFC, which was prepared with fibroblast cells from 14∼14 day mouse fetus. After incubation, we examined their development rates every day and the nuclei numbers of each blastocyst by Hoechst-33342 staining. In the development rates of blastomeres, there were no significant differences between media but the higher rateswere found in the monolayer of MFFC, regardless of reconsititution. In addition, blastomeres cultured with MFFC had slightly greater number of nuclei than those cultured in single media. Generally, the higher development rates of blastomeres were found from earlier stage embryos than the later ones, regardless of culture conditions. Reconsitituted blastomeres had more nuclei but did not show the higher development rates, compared to the single blastomeres. Taken together, our results suggest that co-culture with MFFC have a beneficial effect on the in vitro development of blastomeres from mouse embryos.

• Korean Journal of Animal Reproduction
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• v.24 no.3
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• pp.263-268
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• 2000

The development of single blastomeres isolated from 2-, 4- and 8-cell mouse embryos and the ability of such blastomeres to survive slow freezing were studied. Of 223, 60 and 188 single blastomeres isolated from 2-, 4- and 8-cell mouse embryos, respectively, 111 blastomeres (49.8%) from 2-cell embryos, 12 blastomeres (20.0%) from 4-cell embryos and blastomeres (16.5) from 8-cell embryos developed into blastocysts after culture for 96 hrs. The recovery rate was 54.2% (65/120), 46.4% (13/28) and 24.3% (17/70) of blastomeres derived from 2-, 4- and 8-cell embryos following freezing and thawing and the survival of frozen-thawed blastomeres was 27.1% (16/59), 36.4% (4/11) and 17.6% (3/17), and respectively. The apparently six normal fetuses were obtained from frozen-thawed blastomere from 2-cell embryos after transferring into the recipients. These results indicate that mouse btastomeres isolated from preimplatation stage embryos can survive storage in liquid nitrogen following slow freezing.

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.357-363
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• 1994

To investigate the effect of extracellular matrix proteins on the in vitro development of blastomeres isolated from 2, 4, and 8-cell embryos(termed 1/2, 1/4 and 1/8 blastomeres, respectively) of ICR strain mice, those were cultured in fibronectin, gelatin, or collagen precoated culture dishes containing 1.5ml of NaHCO3-BMOC-3 medium at 37$^{\circ}C$ for 72 hrs, under the atmosphere at 5% CO2. and 95% air. Fibronectin, gelatin, or collagen significantly(P<0.01) increased and blastocyst formation rate compared with controls in 1/2(65.3, 59.2, 60.7% vs. 21.6%), 1/4(63.7, 53.4, 57.1% vs. 26.3%), and 1/8 blastomeres(61.1, 52.3, 53.7% vs. 19.1%). Both the nuclear number(P<0.05) and diameter of blastocysts(P<0.01) developed from balstomeres were significantly affected by the origin of blastomeres. The nuclear number of blastocysts developed from 1/2, 1/4, and 1/8 blastomeres ranged 29.3$\pm$1.6, 24.5$\pm$1.3, and 20..$\pm$1.2, respectively. And the diameter of those blastocysts was 88.3$\pm$2.4, 57.6$\pm$2.1, 39.8$\pm$1.9${\mu}{\textrm}{m}$, respectively.

• Journal of Embryo Transfer
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• v.8 no.2
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• pp.75-82
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• 1993

To investigate the effect of EDTA on the in vitro development of blastomeres isolated from 2, 4, and 8-cell embryos(termed 1 /2, 1 /4 and 1 /8 blastomeres, respectively) of ICR strain mice, those were cultured in vitro in 35 mm culture dishes containing NaHCO$_3$-BMOC-3 medium supplemented with 10, 50, 100, or 500 $\mu$M of EDTA at 37$^{\circ}C$ for 72hrs. under the atmosphere of 5% $CO_2$and 95% air. EDTA supplementation of 10, 50, or 100 $\mu$M to medium significantly(P<0.01) increased blastocyst formation rate compared with controls in 1 /2(58.3, 63.7, and 61.3% vs 21.6%), 1 /4(54.7, 57.5 and 62.2% vs. 2L3%), and 1 /8 blastomeres(46.2, 48.7, and 57.7% vs. 19.1%). Whereas, it was significantly(P<0.01) decreased to 4.5, 2.3, and 2.0% for 1 /2, 1 /4 and 1 /8 blastomeres, respectively by the EDTA supplementation of 500 M Both the nuclear number(P<0.05) and diameter of blastocysts(P<0.01) developed from balstomeres were significantly affected by the origin of blastomeres. The nuclear number of blastocysrs developed from 1/2, 1/4, and 1/8 blastomeres ranged 28.3i1.3, 24.18i1.2, and 19.84$\pm$0.9, respectively. And the diameter of those blastocysts was 87.2$\pm$1.1, 56.4$\pm$0.9, and 39.2$\geq$0.8 $\mu$M, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.15-22
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• 2003

Experiments were conducted to evaluate the effect of blastomere diameters and cell cycle stages on the subsequent development of nuclear transplant rabbit embryos (NT-embryos) using nuclei derived from the 16- or 32-cell stage embryos. All blastomeres and NT-embryos were cultured individually in modified Ham's F-10 medium supplemented with 10% rabbit serum (RS) at $38^{\circ}C$ and 5% $CO_2$ in air. The diameter of blastomeres from 16-cell stage embryos was found twice of those from 32-cell stage (51 vs 27 ${\mu}m$). Significant differences were observed in cleavage rates ($\geq$3 divisions) in the isolated single blastomeres (54 vs 48 for 16-cell; 28 vs 14 for 32-cell, p<0.05), but the fusion rates of oocytes with transferred nuclei were similar between small and large single blastomeres derived from either 16-cell or 32-cell stage embryos. When 16-cell stage blastomeres were used as nuclear donors, cleavage rates ($\geq$3 divisions) of the NT-embryos were greater in the small nuclear donors than in the large donors (73 vs 55%, p<0.05). On the contrary, significantly higher cleavage (43 vs 6%, p<0.05) and developmental rates (14 vs 0%, p<0.05) were observed in the large blastomere nuclear donor group of the 32-cell stage embryos. When the cell cycle stages were controlled by a microtubule polymerization inhibitor (Demicolcine, DEM) or the combined treatment of DEM and Aphidicolin (APH), a DNA polymerase inhibitor, fusion rates were 88-96% for the 16-cell donor group (without DEM treatment), which were greater than the 32-cell donor group (54-58%). Cleavage rates were also greater in the transplants derived from G1 nuclear donor group (93-95%) than those from the DEM and APH combined treatment (73%) for the 16-cell donor group (p<0.05). No significant difference was detected in the morula/blastocyst rates in either donor cell stage (p>0.05). In conclusion, it appeared that no difference in the developmental competence between large and small isolated blastomeres was observed. When smaller 16-cell stage blastomeres were used as nuclear donor, the cleavage rate or development of NT-embryos was improved and was compromised when 32-cell stage blastomeres were used. Therefore, control nuclear stage of the donor cell at $G_1$ phase in preactivated nuclear recipients seemed to be beneficial for the cleavage rate of the reconstructed embryo in the 16-cell transplant, but not for subsequent morula or blastocyst development.

• Journal of Veterinary Clinics
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• v.10 no.2
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• pp.243-249
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• 1993

Although plenty of experiments for production of genetically identical twins have been reported, most of these reports were focused on microsurgical bisection of morula stage embryos, and little research has been performed for the production with frozen emb교os. The objective of these experiments were to assess the in vitro and in vitro developmental potential of blastomeres isolated from frozen-thawed 4-cell and 8-cell mouse embryos and to produce the identical multiplets from those embryos. The percentages of isolated 1/4, 2/4, 4/4, (control), 1/8, 2/8, 3/8, 4/8 and 8/8(control) blastomeres of 4-cell and 8-cell mouse emb교os which developed to normal blastocyst were 38.7%, 73.6%, 96.2(control), 15.1%, 40.1%, 65.9%, 88.3%, and 98.5%(control), respectively. The percentages of isolated 1/4, 2/4, 4/4(control), 1/8, 2/8, 3/8, 4/8 and 8/8(control) blastomeres of frozen-thawed 4-cell and 8-cell mouse embryos which developed to normal blastocyst were 35.6%, 68.5%, 100.0%(control), 16.1%, 50.6%, 71.7%, 90.9% and 100.0%(control), respectively. Normal 26 pups were obtained by transfer of 240 blastocyts developed 1, on 1/4 to 8/8 blastomeres. Those 26 pups obtained, 4 identical twins were produced from 2/4, 2/8, 3/8 and 4/8 blastomeres.

• Journal of Embryo Transfer
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• v.10 no.2
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• pp.171-175
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• 1995

This study was performed to establish the condition and the methods for the techniques of insertion the isolated blastomere cells into cytoplasm, in order to research the develop-mental ability of bovine embryo blastomere cells in vitro produced. After 24h in vitro ovary maturation with the ovaries from a slaughter house, in vitro fertilization was performed to the vital sperms which their mobility were decided by percoll gradient method, with 2~8 cell stage embryos, the blastomeres were isolated in $Ca^2$+. $Mg^2$+-free PBS, and following that embedded into agar and alginate solution, respectively. The rates of in vitro develop-ment are as follows ; in agar embedded 11 among 120(9.2%) 1 /2~1 /3 blastomers cleaved and 6 among 93(6.5%) 1 /4~1 /8 blastomeres cleaved. In sodium alginate-embedded 14 among 84(16.7%) 1 /2~1 /3 blastomeres cleaved and 6 among 85(7.1%) 1 /4~1 /8 blastomeres cleaved. In case of Na-alginate, the rate of the cells were better than those of agar. The results suggest that the techniques for embeeding the isolated blastomeres into gel may help cloning of bovine early embryo without nuclear transplantation.