• Journal of Embryo Transfer
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• v.20 no.3
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• pp.191-200
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• 2005

Many studies have shown that the development of mouse early 2-cell embryos in vitro is related with the intracellular $Ca^{2+}$ changes. In ICR strain mouse, the development of embryos arrests at early 2-cell stage, but the arrested early 2-cell embryos can be rescued by the addition of $Ca^{2+}$-related materials. Acetylcholine (ACh) increases intracellular $Ca^{2+}$ concentration ([$Ca^{2+}$]i) via the mAChR-PLC-IP3 pathway in mouse oocytes. We examined whether ACh rescues 2-cell block in mouse. In early 2-cell embryos, ACh increased [$Ca^{2+}$]i in a dose-dependent manner (p<0.001), and had an effect on rescue of 2-cell block and embryonic development. To identify the signal pathway involved in ACh-induced rescue of 2-cell block, we first applied an agonist of ACh receptor (AChR). Like ACh, carbachol increased intracellular $Ca^{2+}$ concentration ([$Ca^{2+}$]i) and atropine, an antagonist of ACh receptor, blocked the ACh-induced $Ca^{2+}$ increase. In $Ca^{2+}$-free medium, ACh also increased [$Ca^{2+}$]i, indicating that $Ca^{2+}$ increased by ACh is mainly released from the intracellular $Ca^{2+}$ store. The ACh-induced $Ca^{2+}$ increase was blocked by PLC inhibitor (U73122), ryanodine receptor (RyR) antagonist (dantrolene), and CaM KII inhibitor (KN-93), but not by IP3R antagonists (xestospongin C). These results show that ACh increases intracellular $Ca^{2+}$ concentration via mAChR/PLC/RyR, and this contributes to the rescue of 2-cell block.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.7-8
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• 2003

Since it was first reported in 1997, somatic cell cloning has been demonstrated in several other mammalian species. On the mouse, it can be cloned from embryonic stem (ES) cells, fetus-derived cells, and adult-derived cells, both male and female. While cloning efficiencies range from 0 to 20%, rates of just 1-2% are typical (i.e. one or two live offspring per one hundred initial embryos). Recently, abnormalities in mice cloned from somatic cells have been reported, such as abnormal gene expression in embryo (Boiani et al., 2001, Bortvin et al., 2003), abnormal placenta (Wakayama and Yanagimachi 1999), obesity (Tamashiro et ai, 2000, 2002) or early death (Ogonuki et al., 2002). Such abnormalities notwithstanding, success in generating cloned offspring has opened new avenues of investigation and provides a valuable tool that basic research scientists have employed to study complex processes such as genomic reprogramming, imprinting and embryonic development. On the other hand, mouse ES cell lines can also be generated from adult somatic cells via nuclear transfer. These 'ntES cells' are capable of differentiation into an extensive variety of cell types in vitro, as well assperm and oocytes in vivo. Interestingly, the establish rate of ntES cell line from cloned blastocyst is much higher than the success rate of cloned mouse. It is also possible to make cloned mice from ntES cell nuclei as donor, but this serial nuclear transfer method could not improved the cloning efficiency. Might be ntES cell has both character between ES cell and somatic cell. A number of potential agricultural and clinical applications are also are being explored, including the reproductive cloning of farm animals and therapeutic cloning for human cell, tissue, and organ replacement. This talk seeks to describe both the relationship between nucleus donor cell type and cloning success rate, and methods for establishing ntES cell lines. (중략)

• Korean Journal of Animal Reproduction
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• v.18 no.2
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• pp.87-94
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• 1994

The objective of this study is to evaluate the developmental ability of mouse embryo in the presence of human amniotic fluid (hAF), The highest development rate was found in the culture media supplemented with 20% mid-term hAF but this rate was concomitantly reduced with more than 20% hAF. Furthermore, mouse two-cell embryos cultured in 20% mid-term hAF were developed more consistently to the expanded and hatched blastocyst stages compared to those cultured in simple medium. However, no significant differences in the embryo development rates were observed among the supplemented effects of 20% mid-term hAF, 0.3% bovine serum albumin (BSA), and 10% fetal calf serum (FCS), Development rates of two-ceiI mouse embryos cultured in 20% full-term hAF were declined compared to 20% mid-term hAF. Outgrowth of hatched blastocysts were observed when the embryos were cultured in medium containing 20% mid-term hAF or 10% FCS. But two-cell mouse embryos cultured in the presence of 20% full-term hAF or O.3% BSA was not observed their outgrowth. The kinetics of outgrowth processes in the presence of hAF were similar to those with 10% FCS. However, embryos with FCS showed a considerably greater extents of trophetodermal cell proliferation and outgrowth. Taken together, these data suggest that mid-term hAF may have a suitability for the mammalian embryos and induce embryonic outgrowth.

• Clinical and Experimental Reproductive Medicine
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• v.22 no.2
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• pp.191-201
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• 1995

Transcriptional activation of the embryonic genome initiates at 2-cell stage in mouse embryo and is characterized by the synthesis of TRC which is restricted to 2-cell stage. To investigate the roles of various protein kinases on the embryonic gene activation, the effects of protein kinase inhibitors on in vitro development and protein synthetic profiles of the early mouse embryos were examinded. None of ${\alpna}-amanitin$ which is a mRNA synthetic inhibitor, H8 which is a PKA inhibitor, and H7 which is a PKC inhibitor, affected on first cleavage of mouse 1-cell embryos in vitro. However, all of these drugs inhibited the second cleavage. When the drugs were removed following treatment for 6 hours, H8 or H7 treatment showed little inhibition on subsequent development of 1-cell embryos to 2-cell stage or further. In contrast, ${\alpna}-amanitin$ irreversibly inhibited the development of 1-cell embryos to 2-cell stage following removal of the drug. Genistein, a TPK inhibitor, inhibited both the first cleavage of 1-cell embryos and the second cleavage of 2-cell embryos, suggesting that TPK activity may be important during the early cleavages. All of the above four drugs inhibited TRC synthesis as shown by the fluorographic analysis of $[^{35}S]-Met$ labeled protein profiles. When late 1-cell embryos were treated with H7 and analyzed synthetic patterns of $[^{35}S]-Met$ labeled protein, the quantitative differences of protein synthesis on SDS-PAGE appeared on 77 kD and 33 kD region at $32{\sim}38$ hours post hCG. From these studies, transcriptional activation of embryonic genome is not essenting to the mouse 1-cell embryos to develop to 2-cell stage. Hawever, TPK activity is reguisite for both the first cleavage and second cleavage. Similarly, both PKC and PKA activities are required for the second cleavage of mouse embryos, but not for the first cleavage.

• Journal of Embryo Transfer
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• v.12 no.3
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• pp.283-291
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• 1997

In vitro development of bovine embryos is affected by many factors such as energy substrates, amino acids, and some growth factors. It has been reported that mRNA of insulin, PDGF and their receptors are detected in cow embryos, and that some chelating agents such as EDTA and transferrin have beneficial role on mouse and bovine embryos. The author hypothesized that insulin, transferrin arid PDGF added to a culture medium increase in vitro development of bovine embryos by chelating toxic substance(s) or increasing cell growth and metabolism. Immature oocytes from slaughtered ovaries of Holstein cows and heifers were matured for 24 hours in a TCM199 containing 10% fetal calf serum, FSH, LH and estradiol with granulosa cells in vitro. Matured oocytes were coincubated with sperm for 30 hours in a modified Tyrode's medium (IVF). Embryos cleaved to 2- to 4-cell at 30 hours after IVF were selected and cultured in a 30-$\mu$l drop of a synthetic oviduct fluid medium (SOFM) containing 0.8% BSA, Minimum Essential Medium essential and non-essential amino acids, and insulin, transferrin or PDGF for 9 days. Supplementation of a SOFM with insulin, and /or transferrin did not increase develop-mental rate to expanding and hatching blastocyst of 2- to 4-cell bovine embryos compared with control. The highest developmental rate to hatching blastocyst was shown when PDGF was added at the concentration of 10 ng /ml among the supplementing doses tested in the present study (p<0.05). Addition of PDGF without insulin to a SOFM could not increase embrye development, but combined addition of PDGF with insulin significantly increased (p<0.05) embryo development to hatching blastocyst (50%) compared with control (38%). In conclusion, insulin and PDGF supplemented to a SOFM may act synergistically and have beneficial effect on in vitro development of 2- to 4-cell bovine embryos matured and fertilized in vitro.

• Journal of Embryo Transfer
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• v.15 no.3
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• pp.247-253
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• 2000

This study was undertaken to optimize enucleation and reconstitution methods for the production of cloned mice by somatic cell nuclear transfer Outbred ICR mouse oocytes at the metapahse- II stage were retrieved from female mice superovulated by PMSG and hCG. In Experiment 1, oocytes were enucleated in medium supplemented with cytochalasin B (CCB) of 3 levels (0, 7.5 or 15 $\mu\textrm{g}$/mL), and higher rate of encleation was obtained at 7.5 and 15 $\mu\textrm{g}$/mL than at $\mu\textrm{g}$/mL. In Experiment 2, oocytes enucleated in 7.5 $\mu\textrm{g}$/mL CCB-containing medium were reconstituted with different types of somatic cell by following methods; 1) cumulus cells by direct cell injection, 2) cumulus cells by electric fusion (1.25 kV/cm, 2 pulses for each 70 $mutextrm{s}$) or 3) STO cells by the electrofusion. Electrofusion of STO cells with enucleated oocytes yielded the greatest (P<0.05) rate of reconstitution without lysis (76%) than any other combinations. Although significant decrease in the rate of somatic cell introduction was found, the electrofusion of cumulus cells yielded better rate of reconstitution than direct injection (0 vs. 18%). In Experiment 3, the duration of electric stimulation for the fusion was changed to either 50 $mutextrm{s}$ or 90 $mutextrm{s}$, but no significant improvement of reconstitution efficacy was obtained. In conclusion, this study showed that ICR mouse oocytes could be used for the production of reconstituted oocytes and a fusion method of 1.25 KV/cm with 2 pulses using 570 cell was the optimal.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.94-94
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• 2002

Lactadherin (formerly known as BA46), a major glycoprotein of the human milk fat globule membrane, is abundant in human breast milk and breast carcinomas and may prevent symptomatic rotavirus infections. In this study, under the control of mouse whey acidic protein (WAP) promoter, the expression pattern of lactadherin (Ltd) in lactogenic hormone-dependent mouse mammary epithelial cell line HC11 were tested. pLNWLtd construct containing 2.4 kilobases of the WAP promoter and 1.5 kilobases of human lactadherin gene was stably transfered into HC11 cells using retroviral vector system. Integration and expression level of the transgene was estimated using PCR and RT-PCR, respectively. Prominent induction of Ltd gene under the WAS promoter was accomplished in the presence of insulin, hydrocortisone and prolactin, while induction with insulin alone resulted in lower expression. Our results demonstrate that the expression of the transgene is increased by synergistic effect of several lactogenic hormones, including insulin, hydrocortisone, and prolactin.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.52-52
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• 2003

Granulocyte-macrophage colony stimulating factor (GM-CSF) is synthesized in the female reproductive tract and has been shown to play an important role in human and murine embryo development and implantation. However, the mechanism of GM-CSF on the embryo development is unknown. Recent studies suggested that GM-CSF may be increase the expression of implantation relented genes, such as interleukin-1 (IL-1) system. Our aim of this study was to compare the interleukin-1$\alpha$ (IL-1$\alpha$), interleukin-1$\beta$ (IL-1$\beta$) and interleukin-1 receptor antagonist (IL-lra) mRNA between the GM-CSF supplemented group and control group in mouse embryos. Mouse 2-cell embryos were cultured in P-1 medium supplemented with or without mouse GM-CSF (10 ng/ml). The number of total and apoptotic cell in blastocyst were assessed by TUNEL. And then, the expression of IL-1$\alpha$, IL-1$\beta$ and IL-1ra mRNA in blastocyst were examined by RT-PCR.

• Clinical and Experimental Reproductive Medicine
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• v.45 no.3
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• pp.110-115
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• 2018

Objective: To compare our in-house method of embryo freezing with Cryotop vitrification in terms of immediate survival, subsequent cleavage and blastocyst formation, and cell numbers in blastocysts. Methods: Two-cell mouse embryos were randomly allocated into three groups: a non-frozen control group (group 1, n = 300), a group that underwent Cryotop vitrification (group 2, n = 300), and a group that underwent our in-house freezing method (group 3, n = 300). Results: There were no significant differences between groups 2 and 3 in the immediate survival rate (96.3% vs. 98.6%, respectively; p= 0.085), the further cleavage rate (91.7% vs. 95.0%, respectively; p= 0.099), or the blastocyst formation rate (80.7% vs. 78.6%, respectively; p= 0.437). The cell numbers in the blastocysts from groups 1, 2, and 3 were comparable ($88.99{\pm}10.44$, $88.29{\pm}14.79$, and $86.42{\pm}15.23$, respectively; p= 0.228). However, the percentage of good-quality blastocysts in the Cryotop vitrification group was significantly higher than in the group in which our in-house method was performed, but was lower than in the control group (58.0%, 37.0%, and 82.7%, respectively; p< 0.001). Conclusion: At present, our method is inferior to the commercial Cryotop vitrification system. However, with further improvements, it has the potential to be useful in routine practice, as it is easier to perform than the current vitrification system.

• Clinical and Experimental Reproductive Medicine
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• v.42 no.3
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• pp.94-100
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• 2015

Objective: The goal of this study was to ascertain optimal assisted hatching (AH) method in frozen embryo transfer. We compared the effect of depending on whether mechanical or laser-AH was performed before or after the vitrification of embryo development rate and blastocyst cell numbers. Methods: In order to induce superovulation, pregnant mare's serum gonadotropin followed by human chorionic gonadotropin were injected into 4- to 5-week-old female mice. 2-cell embryos were then collected by flushing out the oviducts. The Expanded blastocysts were recovered after the collected embryos were incubated for 48 hours, and were then subjected to artificial shrinkage (AS) and cross-mechanical AH (cMAH) or quarter-laser zona thinning-AH (qLZT-AH) were carried out using the expanded blastocysts before or after vitrification. After 48 hours of incubation, followed by vitrification and thawing (V-T), and blastocysts were fluorescence stained and observed. Results: The rate of formation of hatched blastocysts after 24 and 72 hours of incubation was significantly higher in the AS/qLZT-AH/V-T group than in the other groups (p<0.05). The cell number of the inner cell mass was higher in AS/V-T/non-AH and AS/V-T/cMAH groups than those of others (p<0.05). In the control group, the number of trophectoderm and the total cell number were higher than in the AS-AH group (p<0.05). Conclusion: The above results suggest that AS and AH in vitrification of expanded blastocysts lead to the more efficient formation of hatched blastocysts in mice.