• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.56-56
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• 2001

The exogenous gene transfer by intracytoplasmic sperm injection (ICSI) procedure has been recently used to produce transgenic mice and pigs. Sperm-mediated DNA transfer has the potential to markedly simplify the generation of transgenic animals. This method may serve as an alternative to the pronucleus injection of DNA for the production of transgenic pigs. Therefore, in this study, we investigated the expression of transgene after co-injection of spermatozoon or sperm head with green fluorescent protein (GFP) gene into in vitro matured porcine oocytes. Spermatozoon and sperm head, that was obtained by sonication, were treated with 0.03% Triton X-100 to remove the membrane. They were preincubated with linearized pEGFP-N1 for 1 min, and then embryos cultured NCSU23 medium for 2.5 days after co-injected of sperm and DNA. We monitored expression of GFP in embryos under epifluorescent microscope. The remove of sperm membrane did not alter the developmental competence of embryos after ICSI. At 7 days following injection, the rates of blastocysts following injection of intact sperm (15.0%), and of sperm with disrupted membrane (14.2%) were higher than that following IVF (10.0%). Porcine oocytes injected with sperm which co-cultured with DNA concentration of 1, 0.1, and 0.01 ng were 60, 65.7 and 75% and 18.5, 37.4 and 22.2% for rates of cleavage and GFP expression, respectively. In vitro matured porcine oocytes injected with sperm and isolated sperm head resulted in 69 and 59.7% of cleavage rates, respectively The rates of embryo GFP expressed did not significantly different between sperm (20.4%) and sperm head (20.0%) injection. The transgenic embryos with the clusters of positive blastomeres were observed under fluorescent microscope. Most of embryos expressed GFP gene showed mosaicism. They showed GFP expression at 1/4, 2/4 and 3/4 of blastomeres at the 4-cell stage. Among these 4-cell embryos, the expression rate of 1/4 blastomere group (54.6%) was higher than the other groups (15.3-30.7%). These results indicate that membrane disrupted sperm could attach with exogenous DNA, and that this procedure may be useful to introduce foreign gene into porcine oocytes. Therefore, our data suggest that the ICSI car be a useful tool to efficiently produce transgenic pig as well as other mammals.

• Development and Reproduction
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• v.4 no.1
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• pp.7-12
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• 2000

At fertilization, sperm penetrates into oocyte, male and female pronuclei are fused together, and mitotic division follows. However, little information is available on the interactive roles and dynamic processes between cytoplasmic and nuclear components during the pronuclear formation, migration and cell division. The assisted reproductive technologies such as, intracytoplasmic sperm injection (ICSI) and round spermatid injection(ROSI) could provides new treatments for the male infertility as well as tools for the study of basic mechanism during fertilization. Nuclear transfer can also provide a mechanism on the interactive roles between nucleus and cytoplasm since the process includes nuclear reprogrammming of differentiated cells in the enucleated oocytes. Recently, I have investigated developmental processes in porcine oocytes following fertilization parthenogenesis, ICSI, ROSI and nuclear transfer using indirect immunocytochemical and electron microscopic studies. The results could provide an insight into biological questions related with epigenesis as well as strategies for the enhancement of embryology in general such as ICSI and nuclear transfer.

• Clinical and Experimental Reproductive Medicine
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• v.43 no.3
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• pp.181-184
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• 2016

The aim was to report a healthy live birth using re-vitrified-warmed cleavage-stage embryos derived from supernumerary warmed embryos after frozen embryo transfer (ET) in a patient with recurrent implantation failure (RIF). The case was a 39-year-old female with a history of polycystic ovarian syndrome and adenomyosis, along with RIF. After ovarian hyperstimulation, 33 cumulus-oocyte complexes were retrieved and fertilized with conventional in vitro fertilization and intracytoplasmic sperm injection. Because of the risk of ovarian hyperstimulation syndrome, 16 grade B and C embryos were vitrified. After 3 and 6 months, 3 and 4 B-C warmed embryos were transferred to the uterus, respectively. However, implantation did not take place. Ten months later, four embryos were warmed, two grade B 8-cell embryos were transferred, and two embryos were re-vitrified. One year later, the two re-vitrified cleavage-stage embryos were warmed, which resulted in a successful live birth. This finding showed that following first warming, it is feasible to refreeze supernumerary warmed embryos for subsequent ET in patients with a history of RIF.

• 대한생식의학회:학술대회논문집
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• 1999.05a
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• pp.45-52
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• 1999

포유동물의 수정은 정자가 난자내로 침입함으로써 시작되는데 이때 정자는 부계의 유전물질 이외에도 다양한 후성적 요소들 (epigenetic factors), 즉 난활성 인자, 중심체, 부계 유래의 mitochondria 및 부계 특이 삽입 유전자 등을 난자에 전달해 준다. 하지만 수정 및 초기 배발달동안 정자에 의해 전달된 후성적 요소들의 역할과 기능적 발현 및 억제 기전에 관해서는 명확히 알려져 있지 않다. 수정보조기법인 ICSI 및 ROSI의 개발은 남성불임치료에 혁신적인 기술로 자리잡고 있을 뿐만 아니라 포유동물의 수정과정을 이해 하는데 많은 도움을 주고 있다. 본 연구실에서는 최근 몇 년간 돼지난자에 정자, 다양한 정자 구성 요소들, 정낭세포, 및 이종의 정자 등을 미세주입하여 수정을 유도한 후 핵질 및 세포질의 변화과정과 배 발달과정을 살펴 봄으로써, 수정시 정자에 의해 전달되는 후성적 요소들의 기능과 발현 기작을 규명하고자 하였다. 이러한 연구의 결과들은 체외수정, ICSI, ROSI 등의 임상치료기술의 개선에 기초자료로 활용될 수 있으리라 생각한다.

• Clinical and Experimental Reproductive Medicine
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• v.45 no.3
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• pp.101-109
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• 2018

In an age when a small quantity of sperm can lead to pregnancy through in vitro fertilization or intracytoplasmic sperm injection, selecting healthy sperm is important. Sperm DNA fragmentation (SDF) is known to be higher in infertile men. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) and the alkaline comet test are SDF tests that directly measure DNA damage and have shown closer correlations with assisted reproduction results than indirect tools such as the sperm chromatin structure assay or the sperm chromatic dispersion test. It is difficult; however, to endorse a single test as the best test overall; instead, it is best to select a testing method based on each patient's clinical condition and goals. In a couple struggling with infertility, if the male partner has a high level of SDF, he should aim to decrease SDF through lifestyle modifications, antioxidant treatment, and ensuring an appropriate duration of abstinence, and physicians need to treat the underlying diseases of such patients. If sperm DNA damage continues despite the patient's and physician's efforts, other methods, such as micromanipulation-based sperm selection or testicular sperm extraction, should be used to select healthy sperm with nuclear DNA integrity.

• Clinical and Experimental Reproductive Medicine
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• v.46 no.3
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• pp.119-124
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• 2019

Objective: It is widely accepted that aging decreases women's fertility capacity. The aim of this study was to assess correlations between maternal age and the morphokinetic parameters and cleavage pattern of embryos. Methods: The morphokinetics of embryos derived from women < 30, 30-35, 36-40, and > 40 years of age were compared retrospectively in terms of time of second polar body extrusion, time of pronuclei appearance, time of pronuclei fading, and time of two to eight discrete cells (t2-t8). Furthermore, abnormal cleavage patterns such as uneven blastomeres at the two-cell stage, cell fusion (Fu), and trichotomous mitoses (TM) were assessed. Results: Only t5 occurred later in women aged 36-40 and > 40 years when compared with those aged < 30 and 30-35 years (p< 0.001). Other morphokinetic timing parameters, as well the presence of uneven blastomeres, were comparable between the groups (p> 0.05). However, Fu and TM were more common in women aged > 40 years than in younger women (p< 0.001). Conclusion: Maternal age was correlated with the cleavage pattern of embryos. Therefore, evaluating embryo morphokinetics may contribute to optimal embryo selection, thereby increasing fertility in patients with advanced maternal age.

• Clinical and Experimental Reproductive Medicine
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• v.45 no.4
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• pp.189-194
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• 2018

Objective: The aim of this study was to compare the rate of maturation, fertilization, and embryo development of in vitro-matured human oocytes derived from pregnant and non-pregnant women. Methods: Immature oocytes were obtained by needle aspiration from 49 pregnant women (group 1) who underwent a cesarean section at term and 77 non-pregnant women (group 2) who underwent a gynecological operation during the same period (8 months). Healthy immature oocytes (530 in group 1 and 539 in group 2) were cultured and assessed for maturation 36 hours later. Mature oocytes were inseminated by intracytoplasmic sperm injection and cultured up to 144 hours. Results: The percentage of degenerated oocytes was significantly higher (12.1% vs. 6.3%; p<0.001) in group 1 than in group 2. There was no significant difference in the maturation rate (66.8% vs. 68.1%; p=0.698), fertilization rate (66.7% vs. 67.6%; p=0.857), or the rate of formation of good-quality blastocysts (46.2% vs. 47.2%; p=0.898) in oocytes obtained from pregnant and non-pregnant women. Conclusion: The developmental competence of immature oocytes did not differ between pregnant and non-pregnant women.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.4
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• pp.362-367
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• 2021

Objective: The impact of early mechanical removal of cumulus cells on fertilization and embryonic development is not yet precisely known. This study aimed to investigate the effects of early and late cumulus cell removal on fertilization, polyspermy, embryonic development potential, blastocyst development, and clinical outcomes. Methods: A prospective study was conducted of patients who underwent in vitro fertilization between September 2019 and October 2020. Sibling oocytes were randomly allocated after insemination to early cumulus cell removal at 6 hours (group I) and late cumulus cell removal at 16-18 hours (group II). If total fertilization failure (TFF) was determined to have occurred at early cumulus cell removal, rescue intracytoplasmic sperm injection (ICSI) was performed. Fertilization, embryonic development, and pregnancy outcomes were compared. Results: A total of 912 oocytes were assigned to group I (458 oocytes) and group II (454 oocytes). Fertilization, polyspermy, embryo quality, and pregnancy outcomes were not significantly different between both groups. Rescue ICSI enabled fertilization of 79.2% of the TFF oocytes. Conclusion: Early cumulus cell removal at 6 hours had no significant difference in fertilization, polyspermy, embryo development, or obstetric and perinatal outcomes compared to late removal. Early cumulus cell removal combined with early rescue ICSI may have the potential to help couples with TFF.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.3
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• pp.132-140
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• 2017

Objective: Correlations between semen parameters and sperm DNA fragmentation index (DFI) were investigated to identify characteristics of sperm without DNA damage that could be used in selecting sperm for intracytoplasmic sperm injection (ICSI). Pregnancy outcomes were compared to determine whether in vitro fertilization (IVF) or ICSI is a better choice for patients who have sperm with a high-DFI. Methods: Semen analysis was carried out in 388 patients who visited our IVF center for the first time to investigate correlations between sperm DFI and semen parameters. In addition, 1,102 IVF cycles in 867 patients were carried out in the present study; 921 cycles in the low-DFI group (DFI < 30%) and 181 cycles in the high-DFI group ($DFI{\geq}30%$). Both the low- and high-DFI groups were subdivided into IVF and ICSI cycle groups. Results: Sperm DFI showed significant inverse correlations with sperm motility (r = -0.435, p< 0.001) and morphology (r = -0.153, p< 0.05). Sperm DFI also showed significant correlations with rapid motility (r = -0.436, p< 0.001), and the kinetic parameters of average-path velocity (r = -0.403) and linearity (r = -0.412). Although there was no significant difference in the pregnancy rates between IVF (48.6%) and ICSI (44.8%) in the low-DFI group, the pregnancy rate of ICSI cycles (44.8%, p< 0.05) was significantly higher than IVF cycles (25.0%) in the high-DFI group. No significant difference was observed in the abortion rates between the low-DFI (52 of 921, 5.6%) and high-DFI groups (7 of 181, 3.8%). Conclusion: ICSI is a better choice than IVF for improving the pregnancy outcomes of patients who have sperm with a high DFI.

• Korean Journal of Animal Reproduction
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• v.23 no.1
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• pp.19-27
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• 1999

This study was carried out to investigate the effect of intracytoplasmic injection of $Ca^{2＋}$ and human sperm extract on the parthenogenetic activation of mouse oocytes. The results obtained were as follows: 1. The mouse oocytes were injected with 10 pl of PBS medium containing 0, 1.7 and 5 mM calcium concentrations, respectively. Activation rate of the oocytes with formation of pronuc1ei and extrusion of the second polar bodies was 14.5, 9.8 and 14.9% at the above calcium concentrations, respectively. There were no significant differences in the activation rates among the calcium concentrations. 2. The mouse oocytes were injected with 10 pl of non-heated human sperm extract, and cultured for 12~15 h in the PBS media with the 0, 1.7 and 5 mM calcium concentrations, respectively. Activation rate(51.8%) of the oocytes at the 1.7 mM calcium concentration was significantly higher than those at the 0 and 5 mM calcium concentrations. 3. The mouse oocytes were injected with 10 pl of heated human sperm extract, and cultured for 12~15 h in the PBS media with the 0, 1. 7 and 5 mM calcium concentrations, respectively. No significant differences were found in the activation rates (11.8~17.0%) among the calcium concentrations. 4. The mouse oocytes were injected with 10 pl of PBS medium, non-heated sperm extract and heated sperm extract, and cultured for 12~15 h in the PBS media with 1.7 mM calcium concentrations, respectively. Activation rate (54.5%) of the oocytes injected with the non-heated sperm extract was highest. There were significant differences in the activation rates among the above injection materials (P＜0.05). 5. The mouse oocytes were injected with 10 pl of 1 and 6 days old non-heated sperm extracts, and cultured for 12＜15 h in the PBS media with 1.7 mM calcium concentrations, respectively. Activation rate(60.0%) of the oocytes injected with 1 days old sperm extract was significantly higher than that (11.1%) injected with 6 days old sperm extract. The results obtained in this study suggest that non-heated human sperm extract may contain sperm-associated oocyte-activating factor such as oscillin.