• Clinical and Experimental Reproductive Medicine
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• v.31 no.4
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• pp.201-207
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• 2004

Objective: The Id family of helix-loop-helix proteins are thought to affect the balance between cell growth and differentiation by negatively regulating the function of basic-helix-loop-helix (bHLH) transcriptional factors. The aim of this study was to investigate the expression pattern of Ids (Id-1, -2, -3, and -4) in preimplantation mouse embryos at mRNA and protein levels. Methods: Oocytes and preimplantation embryos were collected from reproductive organs of female ICR mice following superovulation. RT-PCR was performed to investigate the mRNA expression patterns of Id genes and their protein were localized by immunofluorescence analysis. Results: Id-1 and Id-3 mRNAs were strongly expressed at the germinal vesicle (GV) oocyte and the blastocyst stages. Id-2 mRNA was expressed throughout preimplantation embryo development, but Id-4 was not expressed. Immunofluorescence showed that Id-1 and Id-2 were predominantly localized in cytoplasmic region, but the immunofluorescence signal of Id-3 was weak throughout preimplantation embryo development. Conclusion: These data show for the first time that Ids are expressed in preimplantation mouse embryos and suggest that Ids may play an important role in early preimplantation embryo development and uterine physiological changes.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.69-69
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• 2003

Although effect of TGF$\beta$$_1$ on preimplantation embryo development was reported at mice, little information relevant to this subject is known in bovine. The objectives of this study were to investigate TGF$\beta$$_1$, and TGF$\beta$$_1$ receptors type I and II expression, known as important factors in the embryo development, at unfertilized oocytes and fertilized embryos that will be used as basic data to be compared to NT embryos. We postulated that TGF$\beta$$_1$ may have a beneficial effect on the preimplantation embryo and show different expression patterns as embryo stages change. We have used immunocytochemistry to investigate the presence in unfertilized oocytes and preimplantation embryos of TGF$\beta$$_1$ and the essential components of the TGF$\beta$$_1$ signalling pathway, TGF$\beta$$_1$ receptors type I and II. We found that both receptors, as well as TGF$\beta$$_1$, were present in the unfertilized oocytes. This indicates that TGF$\beta$$_1$, is a maternally expressed protein. At the morulae and blastocyst stages the TGF$\beta$$_1$ receptor type II was not present, but the TGF$\beta$$_1$ receptor type I was present at both stages and we can confirm the TGF$\beta$$_1$ expression of high level at 8-cell stage. These findings support our hypothesis that the TGF$\beta$$_1$, and TGF$\beta$$_1$ receptors may interact with the oocyte and preimplantation embryo, and that TGF$\beta$$_1$ signalling may be important for the development of the oocyte and the preimplahtation embryo.

• Journal of Embryo Transfer
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• v.25 no.3
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• pp.179-187
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• 2010

Embryonic compaction is essential for normal preimplantation development in mammals. The present study was to investigate the effects of compaction patterns on developmental competence of pig embryos. The proportion of blastocyst formation derived from compacted morula was higher than those of compacting and pre-compacting morula (P<0.01). Nuclei numbers of inner cell mass (ICM), trophectoderm (TE), and total of blastocysts derived from compacted group were also superior to those of compacting and pre-compacting groups (P<0.05). Then, compaction patterns, developmental ability and structural integrity were compared between mono- and poly-spermic embryos. The rate of compacted morula in mono-spermic embryos was higher than that of poly-spermic embryos (P<0.05). Especially, the rate of blastocyst formation derived from compacted embryos in mono-spermic embryo group was higher than that of poly-spermic embryo group (P<0.05), although no difference was detected between the two groups in the structural integrity. Finally, we confirmed that beta-catenin was differentially expressed according to compaction patterns in morula and blastocyst stage embryos. In conclusion, our results suggest that the compaction patterns during preimplantation development play a direct role in developmetal competence and quality of pig embryos.

• Development and Reproduction
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• v.2 no.2
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• pp.157-163
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• 1998

Preimplantation embryos of the rat was examined by the morphological changes in the cortical granule envelope (CGE), blastomere surface, and zona pellucida (ZP) of embryo after cortical reaction. The ultrastructural characteristics and CGE of embryos were observed with the scanning electron microscope and fluorescence microscope. In the ultrastructural characteristic of embryo surface, surface microvilli were shortened and the CGE-like structure existed above microvilli in eight-cell embryo. Rough spongy surface and decreased network numbers were key characters of embryonic ZP compared to unfertilized oocyte. The CGE formed by cortical reaction existed in perivitelline space during embryo development but it was thin and locally distributed ill contrast to fertilized oocyte. The present results indicate that cortical reaction forms cortical granule envelope in perivitelline space and causes not only zona hardening, but also ultrastructural changes in ZP and cell membrane of preimplantation embryos.

• Development and Reproduction
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• v.18 no.3
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• pp.153-160
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• 2014

Adaptive development of early stage embryo is well established and recently it is explored that the mammalian embryos also have adaptive ability to the stressful environment. However, the mechanisms are largely unknown. In this study, to evaluate the possible role of aquaporin in early embryo developmental adaptation, the expression of aquaporin (AQP) 5 gene which is detected during early development were examined by the environmental condition. To compare expression patterns between in vivo and in vitro, we conducted quantitative RT-PCR and analyzed localization of the AQP5 by whole mount immunofluorescence. At in vivo condition, Aqp5 expressed in oocyte and in all the stages of preimplantation embryo. It showed peak at 2-cell stage and decreased continuously until morula stage. At in vitro condition, Aqp5 expression pattern was similar with in vivo embryos. It expressed both at embryonic genome activation phase and second mid-preimplantation gene activation phase, but the fold changes were modified between in vivo embryos and in vitro embryos. During in vivo development, AQP5 was mainly localized in apical membrane of blastomeres of 4-cell and 8-cell stage embryos, and then it was localized in cytoplasm. However, the main localization area of AQP5 was dramatically shifted after 8-cell stage from cytoplasm to nucleus by in vitro development. Those results explore the modification of Aqp5 expression levels and location of its final products by in vitro culture. It suggests that expression of Aqp5 and the roles of AQP5 in homeostasis can be modulated by in vitro culture, and that early stage embryos can develop successfully by themselves adapting to their condition through modulation of the specific gene expression and localization.

• Clinical and Experimental Reproductive Medicine
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• v.49 no.4
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• pp.225-238
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• 2022

The ultimate goal of human assisted reproductive technology is to achieve a healthy pregnancy and birth, ideally from the selection and transfer of a single competent embryo. Recently, techniques for efficiently evaluating the state and quality of preimplantation embryos using time-lapse imaging systems have been applied. Artificial intelligence programs based on deep learning technology and big data analysis of time-lapse monitoring system during in vitro culture of preimplantation embryos have also been rapidly developed. In addition, several molecular markers of the secretome have been successfully analyzed in spent embryo culture media, which could easily be obtained during in vitro embryo culture. It is also possible to analyze small amounts of cell-free nucleic acids, mitochondrial nucleic acids, miRNA, and long non-coding RNA derived from embryos using real-time polymerase chain reaction (PCR) or digital PCR, as well as next-generation sequencing. Various efforts are being made to use non-invasive evaluation of embryo quality (NiEEQ) to select the embryo with the best developmental competence. However, each NiEEQ method has some limitations that should be evaluated case by case. Therefore, an integrated analysis strategy fusing several NiEEQ methods should be urgently developed and confirmed by proper clinical trials.

• Development and Reproduction
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• v.2 no.2
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• pp.205-212
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• 1998

A sodium-independent facilitative glucose transporter 1 (Glut1) is a major route by which glucose can be transported across the plasma membrane of mouse embryo. Although it has been known that insulin-like growth factor-I (IGF-I) promotes glucose transport into the mouse embryo, whether IGF-I directly regulates transcription of Glut1 has been uncovered in mouse preimplantation embryo. This study was aimed to elucidate the role of glucose and IGF-I in development and Glut1 expression in preimplantation mouse embryo. Two-cell embryos developed in blastocyst regardless of the glucose in the presence of pyruvate. IGF-I significantly increased the number of blastomeres in the mid-blastula. Deprivation of glucose did not affect the amount of Glut1 transcripts in morula cultured from 2-cell embryo. IGF-I potentiated Glut1 expression in morula cultured from 2-cell embryo even in the absence of glucose. Taken together, it is concluded that depletion of glucose does not promote Glut1 expression the in morula cultured form 2-cell embryo, and that increment of Glut1 expression possibly mediates embryotropic effect of IGF-I on preimplantation mouse embryo.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.5 no.1
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• pp.94-107
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• 2005

Prenatal diagnosis (PND) such as amniocentesis or chorionic villi sampling has been widely used in order to prevent the birth of babies with defects especially in families with single gene disorderor chromosomal abnormalities. Preimplantation genetic diagnosis (PGD) has already become an alternative to traditional PND. Indications for PGD have expanded beyond those practices in PND (chromosomal abnormalities, single gene defects), such as late-onset diseases with genetic predisposition, and HLA typing for stem cell transplantation to affected sibling. After in vitro fertilization, the biopsied blastomere from the embryo is analyzed for single gene defect or chromosomal abnormality. The unaffected embryos are selected for transfer to the uterine cavity. Therefore, PGD has an advantage over PND as it can avoid the risk of pregnancy termination. In this review, PGD will be introduced and application of PGD in inborn error metabolic disorder will be discussed.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.3
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• pp.253-259
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• 2000

Objective: To verify the effect of Matrigel, a ECM complex from Engelbreth-Holm-Swarm (EHS) mouse sarcoma on the preimplantation development and apoptosis of mouse fertilized eggs. Method: Late pronucleus stage eggs were cultured through the blastocyst stage in the presence of Matrigel (0.5%, v/v). Characteristics of apoptosis and cell number assesed by Hoecst staining and TUNEL labeling at the blastocyst stage, respectively. Results: Morphological development, number of cells per embryo was significantly increased but rate and number of TUNEL positive nuclei of the embryo were decreased in the presence of Matrigel. Conclusion: This result suggested that at low concentration of Matrigel improves both viability and morphological development in the preimplantation mouse embryos.

• Clinical and Experimental Reproductive Medicine
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• v.49 no.3
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• pp.159-167
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• 2022

As the resolution and accuracy of diagnostic techniques for preimplantation genetic testing for aneuploidy (PGT-A) are improving, more mosaic embryos are being identified. Several studies have provided evidence that mosaic embryos have reproductive potential for implantation and healthy live birth. Notably, mosaic embryos with less than 50% aneuploidy have yielded a live birth rate similar to euploid embryos. This concept has led to a major shift in current PGT-A practice, but further evidence and theoretically relevant data are required. Proper guidelines for selecting mosaic embryos suitable for transfer will reduce the number of discarded embryos and increase the chances of successful embryo transfer. We present an updated review of clinical outcomes and practice recommendations for the transfer of mosaic embryos using PGT-A.