• Clinical and Experimental Reproductive Medicine
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• 제19권2호
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• pp.117-123
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• 1992

Development in vitro of 2-cell mouse embryos was examined after appropriate exposure to oviductal milieu to demonstrate biological activity present in the oviducts. ICR and ($C57Bl/6{\times}Balb/c$) $F_1$ hybrid mice were superovulated and mated for the recovery of early embryos. Embryos were recoverd at every 2h intervals from 32h post-hCG(hph) to 56 hph. The proportions of developmental stages were determined in the recovered embryos. Development in vitro of 2-cell embryos was more rapid in $F_1$ hybrid than in ICR, showing high proportions of 4-cell embryo and blastocyst at 120 hph. 100% of blastocyst development was obtained at 38hph in $F_1$ hybrid and at 50 hph in ICR when 2-cell embryos were cultured upto 120hph in vitro. Moreover, in vitro culture of oviducts containing 2-cell embryos in ICR mice for 12h from 34hph to 46hph increased developmental capacity of ICR mouse embryo in vitro. The results indicate that oviductal environment contains substances having mitogenic activity and overcoming early cell block in vitro. The mitogenic activity is effective in vitro as well as in vivo.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2001년도 춘계학술발표대회
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• pp.11-11
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• 2001

In this study, we examined the developmental potential of reconstructed bovine embryos and the fate of donor mitochondria during their preimplantation development after nuclear transfer. Isolated cumulus cells were used as donor cells in nuclear transfer. Cumulus cells labelled with MitoTracker Green FM fluorochrome were injected into enucleated bovine MII oocytes and cultured in vitro. MitoTracker labelling on donor cells did not have a detrimental effect on blastocyst formation following nuclear transfer. Cleavage rate was about 69%(56/81) and blastocyst formation rate was 6.2% (5/81) at 7 days after nuclear transfer. The labelled mitochondria dispersed to the cytoplasm and became distributed among blastomeres and could be identified up to the 8- to 15-cell stages. Small patches of mitochondria were detected in some 8- to 15-cell stage embryos (5/20). However, donor mitochondria were not detected in embryos at the 16-cell stage and subsequent developmental stages. In the control group, mitochondria could be identified in arrested 1-cell embryos up to 7 days after nuclear transfer These results suggest that donor mitochondria disappear from recipient cytoplasm before 16-cell stage following nuclear transfer in reconstructed bovine embryos.

• 한국가축번식학회지
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• 제8권2호
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• pp.116-121
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• 1984

These experiments were carried out to examine the effect of rapid thawing (500$^{\circ}C$/min) on the survival of 8-cell mouse embryos cooled slowly (0.5-1$^{\circ}C$/min) to precooling temperatures between -10 and 070$^{\circ}C$ before direct transfer ofembryos to -196$^{\circ}C$, and to compare the survival of embroys thawed slowly (20$^{\circ}C$/min) and rapidly (500$^{\circ}C$/min) after in vitro culture. In addition, the sensitivity of 8-cell mouse embroys to the rate of addition and removal of cryoprotectant at room temperauture, and the effect of developing stages on the survival of embryos frozen-thawed slowly were investigated. The results obtained were summarized as follows: 1. Embryos were survived in rapid thawing (500$^{\circ}C$/min) only when slow cooling was terminated at relatively high subzero teperaure (-20 to -60$^{\circ}C$). The highest survival rate(77.0%) in in vitro culture of embryos thawed rapidly was obtaeined after transfer to -196$^{\circ}C$ from -40$^{\circ}C$. 2. For the survival of embryos in slow thawing (20$^{\circ}C$/min.), slow cooling to lower subzero temperature (-50$^{\circ}C$ and below) was required before transfer of embryos to -196$^{\circ}C$. These results indicate that embryos transferred to -196$^{\circ}C$ from high subzero temprature contain much interacellular ice to damage them during slow warming but to permit survival of embryos after rapid warming. 3. The Survival rate (72.7%) of 8-cell mouse embryos after rapid addition and removal of cryoprotectant, DMSO at room temperature was similar to that (83.9%) after slow addition and removal of cryoprotectant at same temperature. 4. The survival rates of 1-, 2-, 4- and 8-cell embryos frozen-thawed slowly were 26.7, 76.4, 70.0 and 83.9%, respectively.

• 대한수의학회지
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• 제30권4호
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• pp.355-360
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• 1990

포유동물의 초기 발생단계에서 핵의 분화와 전능성(totipotency) 을 규명하고, 수정란의 cloning technique를 개발하여 우량유전자로 조성된 개체를 복제함으로써 효과적인 종축개량 기법으로 응용하기 위하여 생쥐 수정란을 모델로 하여 미세조작기법과 Sendai virus를 이용한 핵융합기술을 이용하여 인위적으로 동일한 유전자를 가진 복제 수정란을 작출하고 이들의 작출효과, 체외발달능력 및 체내 이식후 개체발생여부 등을 조사하였다. 2-세포기, 4-세포기 및 8-세포기의 수정란으로부터 핵을 채취하여 이들을 탈핵된 2-세포기의 수정란에 이식하였을 때, 이들의 핵융합 성공율은 각각 88.6%, 87.1% 및 84.7%이었다. 나아가서 이들 핵융합된 수정란을 체외에서 96시간 배양한 결과, 2-세포기, 4-세포기 및 8-세포기의 핵이 이식된 수정란은 각각 76.5%, 68.4% 및 48.3%가 배반포로 발달하였다. 핵이식 후 체외에서 배반포로 발달된 수정란을 골라 수란생쥐에 이식하였던 바, 2-세포기의 핵이 이식된 수정란 156개 중 58개(37.1%) 가 발달하여 신생자로 생산되었으며, 4-세포기의 핵아 이식된 수정란 135개 중 40개(29.6%)가, 그리고 8-세포기의 핵이 이식된 92개의 수정란 중 15개(16.3%)가 신생자로 생산되었다.

• Journal of Animal Science and Technology
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• 제61권4호
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• pp.225-233
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• 2019

The aim of this study was to produce porcine tetraploid (4N) parthenogenetic embryos using various methods and evaluate their developmental potential. In method 1 (M1), porcine 4N parthenogenetic embryos were obtained by inhibiting extrusion of both first (PB1) and second (PB2) polar bodies; in methods 2 (M2) and 3 (M3), 4N parthenogenetic embryos were obtained by electrofusion of 2-cell stage diploid parthenogenetic embryos derived from inhibition of PB2 or PB1 extrusion, respectively. We found no differences in the rates of cleavage or blastocyst formation or the proportion of 4N embryos among M1, M2, and M3 groups. The different methods also did not influence apoptosis rates (number of TUNEL-positive cells/number of total cells) or expression levels of apoptosis-related BAX and BCL2L1 genes. However, total cell and EdU (5-ethynyl-2'-deoxyuridine)-positive cell numbers in 4N parthenogenetic blastocysts derived from M1 were higher (p < 0.05) than those for M2 and M3 groups. Our results suggest that, although porcine 4N parthenogenetic embryos could be produced by a variety of methods, inhibition of PB1 and PB2 extrusion (M1) is superior to electrofusion of 2-cell stage diploid parthenogenetic embryos derived from inhibition of PB2 (M2) or PB1 (M3) extrusion.

• Asian-Australasian Journal of Animal Sciences
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• 제11권6호
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• pp.655-660
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• 1998

To produce blastocysts more efficiently, it is required to identity accurately the factors involving embryonic cleavage in the chemically defined medium. Effects of pyruvate, lactate, calcium and protein sources on early cleavage of bovine follicular oocytes were investigated. The percentage of IVF embryos cleaved to ${\geq}$ 2-cell or ${\geq}$ 8-cell was higher in pyruvate (+) and lactate (+) (48 or 14%) than in pyruvate (-) and lactate (-) (22% or 4%), than in pyruvate (+) and lactate (-) (28% or 5%) and than in pyruvate (-) and lactate (+) (40% or 10%). Lactate was more effective than pyruvate during early cleavage of bovine embryos in the chemically defined medium. The percentage of IVF embryo cleaved to ${\geq}$ 2-cell and ${\geq}$ 8-cell in calcium (-) (19 and 6%) was significantly (p < 0.05) lower than in calcium (+) (78 and 45%). The percentage of embryos developed to ${\geq}$ 2-cell showed no significant (p < 0.05) difference among BSA, 1 and 20% FBS (57, 57 and 57%). Also the percentage of A grade embryos developed to ${\geq}$ 2-cell showed no significant (p < 0.05) difference among BSA, 1 and 20% FBS (40, 35 and 28%). The percentage of embryos developed to ${\geq}$ 8-cell showed no significant (p < 0.05) difference among BSA, 1 and 20% FBS (33, 23, and 22%). However, the percentage of A grade embryos developed to ${\geq}$ 8-cell in BSA (24%) was significantly (p < 0.05) higher than in 1 and 20% FBS (13 and 8%). The percentage of embryos developed to ${\geq}$ morula showed no significant (p < 0.05) difference among BSA, 1, 10 and 20% FBS (76, 76, 80 and 68%). The percentage of A grade embryos developed to ${\geq}$ morula in 10% FBS (59%) was significantly (p < 0.05) higher than 20% FBS (43%). The percentage of embryos developed to blastocyst showed no significant (p < 0.05) difference among BSA, 1, 10 and 20% FBS (34, 41, 43 and 32%). However, the percentage of A grade embryos developed to ${\geq}$ blastocysts in 10% FBS (25%) was significantly (p < 0.05) higher than in 20% FBS (8%).

• 한국가축번식학회지
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• 제20권2호
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• pp.143-153
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• 1996

To improve the efficiency of nuclear transplantation in the rabbit, this study were evaluated the influence of celly cycle of donor nuclei on the in vitro developmental potential in the nuclear transplant embryos. The embryos of 16-cell stage were collected from the mated does at 48h post-hCG injection and they were synchronized to G1 phase of 32-cell stage. Synchronization of the cell cylce of blastomeres were induced, first, using an microtubules polymerization inhibitor, 0.5$\mu\textrm{g}$/ml colcemid for 10h to arrest blastomeres in metaphase, and secondly, using a DNA synthesis inhibitor, 0.1$\mu\textrm{g}$/ml aphidicolin for 1.5 to 2h to cleave to 32-cell stage and arrest them in G1 phase. The separated G1 phase blastomeres of 32-cell stage were injectied into enucleated recipient cytoplasms by micromanipulation. After culture until 20h post-hCG injection, the nuclear transplant oocytes were electrofused and activated by electrical stimulation. The nuclear transplant embryos were co-cultured for 120h. In vitro cultured embryos were monitored every 24h to assess for development rate. After in vitro cultue for 120h, the nuclear transplant embryos developed to blastocyst stage were stained with Hoechst 33342 dye for counting the number of blastomeres under a fluorescence microscopy. The cleavage rate of blastomeres from 16-cell stage stage rabbit embryos treated with colcemid for 10h or aphidicolin for 6h following colcemid for 10h were not significantly different. The electrofusion rate was similar by high in S and G1 phase donor nuclei as 80.6 and 79.1%, respectively. However, the nuclear transplant embryos using G1 phase donor nuclei were developed to blastocyst at high rate(60.3%) than those using S phase donor nuclei(26.0%). Moreover, the mean blastocyst stage were increased significantly(P<0.05) with the G1 phase donor nuclei(176.6 cells and 1.50 cycles), as compared with the S phase donor nuclei(136.6 cells and 1.42 cycles). These results show that the blastomeres of G1 phase were more successful as donor nuclei in the nuclear transplant procedure, compared with S phase.

• Journal of Animal Science and Technology
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• 제65권4호
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• pp.767-778
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• 2023

The aim of the research is to identify that porcine oocytes can function as recipients for interspecies cloning and have the ability to develop to blastocysts. Furthermore each mitochondrial DNA (mtDNA) in interspecises cloned embryos was analyzed. For the study, mouse-porcine and porcine-porcine cloned embryos were produced with mouse fetal fibroblasts (MFF) and porcine fetal fibroblasts (PFF), respectively, introduced as donor cells into enucleated porcine oocytes. The developmental rate and cell numbers of blastocysts between intraspecies porcine-porcine and interspecies mouse-porcine cloned embryos were compared and real-time polymerase chain reaction (PCR) was performed for the estimate of mouse and porcine mtDNA copy number in mouse-porcine cloned embryos at different stages.There was no significant difference in the developmental rate or total blastocyst number between mouse-porcine cloned embryos and porcine-porcine cloned embryos (11.1 ± 0.9%, 25 ± 3.5 vs. 10.1 ± 1.2%, 24 ± 6.3). In mouse-porcine reconstructed embryos, the copy numbers of mouse somatic cell-derived mtDNA decreased between the 1-cell and blastocyst stages, whereas the copy number of porcine oocyte-derived mtDNA significantly increased during this period, as assessed by real-time PCR analysis. In our real-time PCR analysis, we improved the standard curve construction-based method to analyze the level of mtDNA between mouse donor cells and porcine oocytes using the copy number of mouse beta-actin DNA as a standard. Our findings suggest that mouse-porcine cloned embryos have the ability to develop to blastocysts in vitro and exhibit mitochondrial heteroplasmy from the 1-cell to blastocyst stages and the mouse-derived mitochondria can be gradually replaced with those of the porcine oocyte in the early developmental stages of mouse-porcine cloned embryos.

• Asian-Australasian Journal of Animal Sciences
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• 제19권2호
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• pp.171-175
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• 2006

The aim of this in vitro study was to test the effect of microinjection (Mi) of foreign gene into the rabbit egg pronucleus and epidermal growth factor (EGF) addition on the blastocyst rate, the cell number and the diameter of embryos, and to determine possible relationships between embryo cell number and embryo diameter. Blastocyst rate was significantly decreased in gene- Mi (G-Mi/E0) group (63.1%) comparing to intact ones (83.5%, $p_1$<0.05). The addition of EGF at 20ng/ml (G-Mi/E20) or 200 ng/ml (GMi/ E200) to gene-Mi embryos did not affect blastocyst rate (65.6 and 55.2% resp.). As a control for Mi, the eggs were microinjected with the same volume of phosphate-buffered solution (PBS-Mi) instead of the gene construct solution. Cell numbers and embryo diameters were measured from embryo images obtained on confocal laser scanning microscope. Bonferroni-modified LSD test showed that the embryo cell number in PBS-Mi group was significantly lower ($p_1$<0.05) and in gene-Mi group was tended to decrease compared with intact embryos. Embryo diameter was not different among experimental groups. No effect of EGF given at any doses both on the cell number and embryo diameter was found. A positive correlation between cell number and embryo diameter was observed in all groups of embryos. Since embryo diameter was not changed under the influence of Mi or EGF addition in this study, this seems to be more conservative characteristics of the embryo morphology. These results suggest that the pronuclear microinjection compromises developmental potential of embryos, decreasing blastocyst rate and embryo cell number, whilst embryo diameter is not affected. No effects of EGF on studied parameters were confirmed. Declined quality of Mi-derived embryos is caused by the microinjection procedure itself, rather than by the gene construct used.

• Asian-Australasian Journal of Animal Sciences
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• 제16권1호
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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.