• Development and Reproduction
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• v.10 no.2
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• pp.105-113
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• 2006

Reactive oxygen species(ROS) generated in cellular metabolism have an effect on cell maturation and development. In human reproductive tract, oxidative injury by ROS may induce female infertility. Also, oxidative injury may be responsible for developmental retardation and arrest of mammalian preimplantation embryos. Activating transcription factor 4(ATF4) is a member of the cyclic-AMP response element-binding(CREB) familiy of basic region- leucine zipper(bZip). ATF4 is known to regulate stress response to protect cell from various stress factors and inducer of apoptisis. The purpose of this study was to investigate whether ATF4 is involved in the defensive mechanism in oxidative stress condition during the development of mouse preimplantation embryos. To verify the expression of ATF4 in oxidative stress condition, 2-cell stage embryos were cultured in HTF media containing 0.1mM, 0.5mM or 1mM hydrogen peroxide($H_2O_2$) for 1hr(2-cell), 8hr(4-cell), 17hr(8-cell), 24hr(morula), 48hr(early blastocyst) or 64hr(late blastocyst). The developmental rate decreased in the 0.1mM $H_2O_2$ treated group compared with control group. In embryos treated with 0.5mM and 1mM $H_2O_2$ showed 2-cell block. As a results of the semi-quantitative RT-PCR analysis of SOD1, ATF4 and Bax gene expression, SOD1, ATF4 and Bax genes were increased in 0.1mM, 0.5mM, 1mM $H_2O_2$ treated groups compared with control group. In 2-cell embryos, expression of SOD1, ATF4 and Bax genes were notably increased in 0.1mM, 0.5mM, 1mM $H_2O_2$ treated groups compared with control group. Immunofluorescence analysis showed that ATF4 protein was localized at the cytoplasm of preimplantation embryos. The increase in ATF4 immunoreactivety was observed in the 0.1mM, 0.5mM, 1mM $H_2O_2$ treated groups compared with control group. It suggests that oxidative stress by $H_2O_2$ induces expression of ATF4 and may be involved in protection mechanism in preimplantation embryos from oxidative injury.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.2
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• pp.203-211
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• 1999

목적: 일산화질소 (nitric oxide; NO)는 생식계를 비롯한 여러 생체내 기관에서 다양하고도 중요한 작용을 하는 것으로 알려져 있으며, 복강액은 난관내강과 연결되어 복강액 내의 세포 성분의 변화는 난관의 미세환경을 변화시켜 수정과 초기 배아 발생에 영향을 줄 수 있다. 본 연구는 배아 발생에 있어서 일산화질소의 역할을 이해하고 복강액 내의 NO농도 변화가 배아 발생에 미치는 역할을 조사하기 위해 수행되었다. 방법: 과배란시킨 1세대 잡종 암컷 생쥐 (C57BL${\times}$CBA/Ca)로부터 1세포기 배아를 얻어 10% synthetic serum substitute가 첨가된 modified human tubal fluid 배양액에서 4일 동안 체외배양하였다(대조군). 실험을 위해 이러한 배양조건에 sodium nitroprusside (SNP)를 $0{\sim}1mM$의 다양한 농도로 배양초기부터 첨가하거나, $200{\mu}M$ SNP를 2-, 4-, 8-세포기의 각기 다른 배아시기에 첨가하였으며, 복강경수술을 받는 42명의 여성으로부터 채취한 복강액을 SSS대신 단백질원으로 사용하여 포배아까지의 배아 발달율을 관찰하였으며, 복강액 내의 NO농도를 Griess방법에 의해 측정하였다. 배아의 apoptotic body는 H33342 염색법으로 조사하였으며 배아 발달율은 3회 이상 반복 실험한 결과의 mean${\pm}$SEM으로 나타내었다. 결과: SNP는 농도에 의존적으로 배발생을 억제하였으나 배아 단계에 대한 특이성은 관찰할 수 없었으며, 특히 $100{\mu}M$ 이상의 고농도의 SNP는 2-세포기 단계에서 배아 발생을 정지시켰다. 또한 단백질원으로 복강액 이용시 배 발생율은 복강액 내의 NO 농도에 따라 현저한 차이가 발견되었으며, $2.5{\mu}M$이상의 NO를 함유한 복강액에서 배양한 배아의 발생율은 현저하게 감소하였다. cGMP analogue인 8-bromo-cGMP를 배양액에 첨가시 배아 발생에는 변화가 없었으며, SNP에 의해 배발생이 정지된 2-세포기 배아에서 apoptotic body를 발견할 수 없었다. 결론: 이상의 결과로 보아 NO는 고농도에서 배아 발생을 저해하며, 복강액 내의 NO와 같은 성분의 변화는 배아 발생에 유해한 효과를 유발할 것으로 사료된다. 이러한 NO의 배아 발생 억제효과는 cGMP로 중재되는 경로나 apoptosis유발과는 관계가 없는 것 같다.

• Development and Reproduction
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• v.2 no.1
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• pp.29-37
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• 1998

To investigate the role of oviductal environment in early mammalian development, we examined the effects of bovine oviductal fluid (bOF) on the development of mouse 2-cell embryos in vitro. All of the embryos cultured in medium containing 5% or more of bOF underwent degeneration after 48 hr, whereas only 5% of embryos cultured in the absence of bOF degenerated. When bOF was heated at 65 \circ C for 30 min and then added to the culture medium, the embryotoxic effect of bOF was not removed at all such that none of the embryos remained alive after 48 hr. However, when bOF heated at 90 \circ C for 30 min was added to the culture, nearly most (95%) of embryos was alive. Similarly, pretreatment of bOF with 0.1% chymotrypsin for 1 hr or overnight following heating at 65 \circ C resulted in the development of 95.5% of mouse 2-cell embryos to early blastula after 48 hr culture in the presence of treated bOF. Interestingly addition of an anti-oxidant removed the evbryotoxic effect of bOF so that 91.0% of 2-cell embryos developed to morulae or blastulae in the presence of both 5% bOF and 10 mM of glutathione (GSH) after 48 hr culture. Neither oxidized form of GSH (GSSG) nor other antioxidants, however, could support the embryonic development in the presence of bOF. From these results, it is suggested that bOF contains a protein-like factor(s) which becomes embryotoxic by exposing in vitro, probably via oxidation reaction.

• Development and Reproduction
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• v.7 no.2
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• pp.95-103
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• 2003

Intracellular calcium is an important physiological factor in most cells, and ruthenium red and ryanodine play an important role as calcium modulators. Ruthenium red inhibits calcium-induced calcium release(CICR) from the intracellular calcium store. Ryanodine activates calcium release through ryanodine channel. The present experiment was performed to investigate the effects of two modulators on calcium ion metabolism and to determine their dose-dependency in oocyte and early embryo of mouse. Intracellular calcium ion concentration was measured in realtime by using confocal laser scanning microscope(CLSM) after loading of Fluo-3/AM in mouse oocytes and early embryos. Ruthenium red decreased intracellular calcium ion concentration in oocytes and early embryos at its high concentration(30, 300 $\mu$M). Ryanodine increased intracellular calcium ion concentration in oocytes and early embryos in low concentration(0.01 $\mu$M) but decreased that at higher concentrations(1, 10 $\mu$M). These results indicate that two modulators affected calcium ion metabolism in oocyte and early embryo of mouse, and their dose-dependency was different from somatic cell including myocytes.

• Development and Reproduction
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• v.2 no.1
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• pp.9-20
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• 1998

It has been wel known that phospholipase C(PLC) plays an important role in the intracellular signaling in a variety of cell types. However, involvement of PLC in mouse oocyte maturation and preimplantation embryo development remains unknown. The present study examined the expression patterns of the mouse PLC \beta 1 and \gamma 1 during oocyte maturatio and preimplantation embryo development study examined the expression patterns of the mouse PLC \beta 1 and \gamma 1 during oocyte maturation and preimplantation embryo development by the competitive reverse transcription-polymerase chain reaction (RT-PCR method). PLC \gamma 1 mRNA (0.1 fg) was readily detected in germinal vesicle (GV)-stage oocyte and its level was reduced as meiotic resumption proceeded. PLC-\beta 1 mRNA (<0.1 fg) as detected at low level at GV-stage oocytes and scarcely detected at germinal vescle breakdown (GVBD)-stage oocytes. After fertilization, both PLC \beta 1 and \gamma 1 mRNA levels began to increase at morula-stage embryos (0.2 fg) and were more prominent in blastocyst-stage embryos(1 fg). to elucidate the possible involvement of PLC via protein kinase C(PKC) pathway during oocyte maturation and preimplantation embryo development , the effects of sphingosine (PKC inhibitor), sn-$diC_{8}$(PKC activator) anc U73122 (PLC ingibitor) were examined. Treatment of GV-stage oocytes with sphingosine (20 \mu M) facilitated the meiotic resuption by 10-20 over the control within 1 h as judged by GVBD, whereas U73122 failed to show any significant effect. U73122 (10 \mu M) effectively blocked the compaction of morula, while sn-$diC_{8}$(50 \mu M). In summary, the present study shows that the mouse PLC \beta 1 and \gamma 1 are expressed in a developmental stage-specific manner and PLC-PKC pathway may be involved in early preimplantation embryo development.

• Development and Reproduction
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• v.6 no.1
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• pp.55-66
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• 2002

Embryonic stem cells(ES cells) are derived from the inner cell mass(ICM) of blastocysts, which have the potentials to remain undifferentiated, to proliferate indefinitely in vitro, to differentiate into the derivates of three embryonic germ layers. ES cells are an attractive model system for studying the initial developmental decisions and their molecular mechanisms during embryogenesis. Additionally, ES cells of significant interest to those characterizing the various gene functions utilizing transgenic and gene targeting techniques. We investigated the effects of reproductive hormones, gonadotropins(GTH) and steroids on the induction of differentiation and expressions of their receptor genes using the newly established mouse ES cells. We collected the matured blastocysts of inbred mice C57BL/6J after superovulation and co-cultured with mitotically inactivated STO feeder cells. After 5 passages, we confirmed the expression alkaline phosphatase(Alk P) activity and SSEA-1, 3, 4 expressions. The protocol devised for inducing ES differentiation consisted of an aggregation steps, after 5 days as EBs in hormone treatments(FSH, LH, E$_2$, P$_4$, T) that allows complex signaling to occur between the cells and a dissociation step, induced differentiation through attachment culture during 7 days in hormone treatments. Hormone receptors were not increased in dose-dependent manner. All hormone receptors in ES cells treated reproductive hormones were expressed lower than those of undifferentiated ES cell except for LHR expression in E$_2$-treated ES cells group. After hormone induced differentiation, at least some of the cells are not terminally differentiated, as is evident from the expression of Oct-4, a marker of undifferentiated. To assess their differentiation by gene expression, we analyzed the expression of 7 tissue-specific markers from all three germ layers. Most of hormone-treated group increased in the expression of gata-4 and $\alpha$ -fetoprotein, suggesting reproductive hormone allowed or induced differentiation of endoderm.

• Journal of Embryo Transfer
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• v.29 no.3
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• pp.241-248
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• 2014

This study was carried out to evaluate the effects of embryonic stage, cryoprotectant, and freezing-thawing method on the rates of survival and development of the cryopreserved mouse early embryo and finally to establish the cryopreservation method of surplus embryos obtained during assisted reproductive technology (ART). Two to eight cell embryos were obtained from oviducts of mated $F_1$ hybrid female mice superovulated by PMSG and hCG. Two-step EG, DMSO and 4-step EG, DMSO were used as cryoprotectant and dehydration and rehydration method of embryos, and slow-cooling or rapid-cooling method was used as frozen program. The survival rates of embryos were measured after thawing and rehydration, and the developmental rates of embryos were compared and observed during culturing embryos for 24, 48, 72, 96 hrs. As for the survival and development rates of embryos according to embryonic stage, the survival rate of 2 cell stage in EG and DMSO was significantly higher than 4~8 cell (65.4% versus 61.2%, 81.1% versus 72.5%) (p<0.01, p<0.01), but the development rates of 4~8 cell embryos in EG and DMSO were significantly higher than 2 cell embryos for whole culture period (p<0.01) and the development rates of 4~8 cell embryos in EG were significantly higher than 2 cell embryos in DMSO (p<0.01). As for the survival and development rates of embryos according to cryoprotectant, the survival rate of 2 cell embryo in DMSO was significantly higher than that in EG(77.0% versus 64.4%) (p<0.01), whereas the development rate of embryos was not differ till 24 hrs. The development rate from morular to hatching blastocyst, however, was sinificantly higher in EG than in DMSO during 48 hr (p<0.01). The survival rate of 4~8 cell embryo was 62.5% in EG and 73.3% in DMSO. The development rates of embryo in EG were significantly higher for whole culture periods (p<0.01, 0.05). In respect to the effect of freezing and thawing program on the survival and development rates of embryos, method of slow cooling and rapid thawing was more effective than that of rapid cooling and rapid thawing. The survival rate of embryo in 2 cell stage was higher than in 4~8 cell stage, and EG appears more effective cryoprotectant than DMSO because EG showed better development rates of embryos in 2 and 4~8 cell stage. Moreover, slow cooling and rapid thawing method was considered as the best cryopreservation program.

• Reproductive and Developmental Biology
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• v.39 no.3
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• pp.77-81
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• 2015

This study was carried out to evaluate the effects of embryonic stage and toxicities of cryoprotectant on the rates of survival and development of the cryopreserved mouse early embryo and finally to establish the cryopreservation method of surplus embryos obtained during assisted reproductive technology. Toxicities of two cryoprotectants, dimethyl sulfoxide (DMSO) and ethylene glycol (EG) were investigated using a murine embryo model. Female F-1 mice were stimulated with gonadotropin, induced ovulation with hCG and mated. Two cell embryos were collected and cultured after exposure to either DMSO or EG. Embryo development was evaluated up to the blastocyst stage. The total cell count of blastocysts that were treated with DMSO ($68.1{\pm}24.1$) at the 2-cell stage was significantly lower than that were treated with EG ($81.2{\pm}27.0$) or the control ($99.0{\pm}18.3$) (p<0.001). On comparison of two cryoprotectant treated groups, the DMSO treated group showed a decreased cell count compared with the EG treated group (p<0.05). Both DMSO ($15.4{\pm}1.5$) and EG ($10.2{\pm}1.4$) treated groups showed higher apoptosis rates of cells in the blastocyst compared with the control ($6.1{\pm}0.9$, p<0.0001). In addition, the DMSO treated group showed more apoptotic cells than the EG treated group (p<0.001). The potential toxicity of cryoprotectants was uncovered by prolonged exposure of murine embryos to either DMSO or EG at room temperature. When comparing two cryoprotective agents, EG appeared to be less toxic than DMSO at least in a murine embryo model.

• Development and Reproduction
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• v.9 no.1
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• pp.33-41
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• 2005

Identification of differentially expressed genes at blastocyst stage embryos would provide insights into early development and differentiation. Here, we applied a new differential display reverse transcription polymerase chain reaction(DD RT-PCR) technology, called annealing control primers(ACP) system to identify the genes that are specifically or prominently expressed in mouse blastocysts compared to embryonic stem(ES) cells. Using 100 ACPs, 26 clones were perceived as differentially expressed genes in mouse blastocysts. A BLAST search revealed that cloned genes had significant sequence similarities with known genes in the GenBank/EMBL data base. Among them, 15 genes were selected and conformed by RT-PCR. This analysis suggests that the ACP system is a practical method for the identification of stage-specific genes using small numbers of mouse embryos.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.2
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• pp.183-190
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• 2000

연구목적: 포유류의 착상은 배아가 모체의 자궁벽에 매몰되는 현상으로 부착과 침투 과정을 거쳐 진행되며, 이 과정은 스테로이드 호르몬, 성장인자, 세포점착분자, 그리고 cytokine 등의 상호작용으로 이루어진다. 이 시기에 Interleukin-1 (IL-1)과 leukemia inhibitory factor (LIF) 등이 발현되는 것으로 알려져 있다. 본 실험에서는 이들의 발현이 착상과정에 어떠한 역할을 하는지 그 상관관계를 알아보고자 하였다. 재료 및 방법: 착상 전후의 배아와 자궁내막세포에서 LIF 유전자의 발현양상과 $IL-1{\beta}$와 IL-1 receptor antagonist (IL-1ra)를 처리한 LIF 유전자의 발현양상을 역전사중합효소연쇄반응 (RT-PCR)을 통해 비교하였다. 결과: 배아에서의 LIF 유전자 발현은 in vivo와 in vitro 모두에서 상실기와 포배기에 발현되었고, 자궁내막에서는 임신 1일과 4일째에 발현되었는데, 상실기보다는 포배기에, 그리고 임신 1일보다는 착상시기인 4일째의 자궁내막세포에서 발현양이 많은 것으로 나타났다. 자궁내막세포를 배양한 경우 LIF 유전자는 in vivo에서의 발현양상과 동일하게 임신 1일과 4일에 발현되었으며, 배양액에 $IL-1{\beta}$(500pgml)를 처리하였을 경우 LIF 유전자가 초기 임신 (1~5일) 중 발현되는 것으로 나타났다. 2-세포기 배아의 배양시에 $IL-1{\beta}$를 처리한 경우 8-세포기부터 LIF 유전자가 발현되었으며, 또한 IL-1ea(60 ng/ml)를 배양액에 첨가하였을 경우에는 임신1일째 자궁내막에서는 LIF 유전자가 발현되지 않은 반면, 임신 4일째의 자궁내막세포와 상실기, 포배기 배아 모두에서 LIF 유전자 발현이 감소하는 경향을 보였다. 결론: 이러한 결과는 착상 전후 배아와 자궁내막세포에서 IL-1에 의해 LIF 유전자 발현이 조절되며, 그 결과 착상에 영향을 줄 수 있다는 것을 의미한다. 또한 배아와 자궁내막세포에서 IL-1이 LIF 유전자 발현에 영향을 주는 것으로 보아 착상을 위해 IL-1과 LIF의 상호작용이 중요한 요인이라는 것을 확인할 수 있었다.