• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2002년도 춘계학술발표대회 발표논문초록집
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• pp.4-4
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• 2002

Male germ cell apoptosis has been extensively explored in rodent. In contrast, very little is known about their susceptibility to apoptosis stimuli of developing germ cell stages at the time when germ cell depletion after busulfan treatment occurs. Furthermore, it is still unanswered how spermatogonial stem cells are resistant to busulfan treatment. Spontaneous apoptosis of germ cells was observed in the testis of adult mice and experimentally induced busulfan treated mice increased this apoptosis to such an extent that there was a decrease in the weight of the testis. (omitted)

• 한국수정란이식학회지
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• 제30권3호
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• pp.213-218
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• 2015

In the study for a differentiation and development of spermatogonial cells, the researchers should commonly require a simple, fast and reasonable method that could evaluate the developmental stage of male germ cells without any damage and also relentlessly culture them so far as a cell stage aiming at experimental applications. For developing the efficient method to identify the stage of sperm cells, the morphological characteristics of sperm cells were investigated by staining the cells with blue fluorescent dye Hoechst 33258, and a criterion for male germ cell classification was elicited from results of the previous investigation, then the efficiency of the criterion was verified by applying it to assort the germ cells recovered from male mice in age from 6 to 35 days. As morphological characteristics, spermatogonia significantly differed from spermatocytes in size, appearance and fluorescent patches of nucleus, and spermatids could also be distinguished from spermatozoa by making a difference in the volume and shape of nucleus and the shape and fluorescence of tail. Aforesaid criterion was applicable for classifying in vitro cultured sperm cells by verifying its efficiency and propriety for assorting the stages of testicular germ cells. However, the fluorescent staining showed that germ cells in mouse testis should be dramatically differentiated and developed at 21 days and 35 days of age, which were known as times of sexual puberty and maturity in male mice, respectively. In conclusion, the results indicated that this simple criterion for sperm cell classification using fluorescence staining with Hoechst 33258 may be highly efficient and reasonable for spermatogenesis study.

• Clinical and Experimental Reproductive Medicine
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• 제45권2호
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• pp.75-81
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• 2018

Objective: Recapitulation of the spermatogenesis process in vitro is a tool for studying the biology of germ cells, and may lead to promising therapeutic strategies in the future. In this study, we attempted to transdifferentiate Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) into male germ cells using all-trans retinoic acid and Sertoli cell-conditioned medium. Methods: Human WJ-MSCs were propagated by the explant culture method, and cells at the second passage were induced with differentiation medium containing all-trans retinoic acid for 2 weeks. Putative germ cells were cultured with Sertoli cell-conditioned medium at $36^{\circ}C$ for 3 more weeks. Results: The gene expression profile was consistent with the stage-specific development of germ cells. The expression of Oct4 and Plzf (early germ cell markers) was diminished, while Stra8 (a premeiotic marker), Scp3 (a meiotic marker), and Acr and Prm1 (postmeiotic markers) were upregulated during the induction period. In morphological studies, approximately 5% of the cells were secondary spermatocytes that had completed two stages of acrosome formation (the Golgi phase and the cap phase). A few spermatid-like cells that had undergone the initial stage of tail formation were also noted. Conclusion: Human WJ-MSCs can be transdifferentiated into more advanced stages of germ cells by a simple two-step induction protocol using retinoic acid and Sertoli cell-conditioned medium.

• 한국약용작물학회지
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• 제23권2호
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• pp.138-143
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• 2015

This study was carried out to evaluate the preventive effect of three forms of Korean ginseng roots (fresh, white and red) against bisphenol A (BPA) toxicity in mouse male germ cells (GC-2spd, TM3, TM4). ROS (reactive oxygen species) generation were measured by DCF-DA (2',7'-dichlorohydrofluorescein diacetate) assay. Also, semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) was performed to quantify the mRNA expression levels of apoptosis-related genes, Bax (pro-apoptotic gene) and Bcl2 (anti-apoptotic gene). ROS generation was increased by $50{\mu}M$ BPA, but definitely decreased by treatment with Korean ginseng extracts (fresh, white and red) in mouse male germ cells. In especial, Korean fresh ginseng extract reduced significantly ROS production to normal control. In addition, Korean fresh and white ginseng extracts suppressed the apoptosis of mouse male germ cells by fine-tuning mRNA levels of apoptotic genes changed by BPA. In general, Korean fresh ginseng extract was more effective than white ginseng extract for reducing BPA-induced oxidative stress and apoptosis in mouse male germ cells. Therefore, Korean fresh and white ginseng may help to alleviate biphenol A toxicity in mouse male germ cells.

• 한국동물생명공학회지
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• 제38권2호
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• pp.54-61
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• 2023

Background: Germ cells undergo towards male or female pathways to produce spermatozoa or oocyte respectively which is essential for sexual reproduction. Mesenchymal stem cells (MSCs) have the potential of trans-differentiation to the multiple cell lineages. Methods: Herein, rat MSCs were isolated from bone marrow and characterized by their morphological features, expression of MSC surface markers, and in vitro differentiation capability. Results: Thereafter, we induced these cells only by retinoic acid supplementation in MSC medium and, could able to show that bone marrow derived MSCs are capable to trans-differentiate into male germ cell-like cells in vitro. We characterized these cells by morphological changes, the expressions of germ cell specific markers by immunophenotyping and molecular biology tools. Further, we quantified these differentiated cells. Conclusions: This study suggests that only Retinoic acid in culture medium could induce bone marrow MSCs to differentiate germ cell-like cells in vitro. This basic method of germ cell generation might be helpful in the prospective applications of this technology.

• Toxicological Research
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• 제17권4호
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• pp.241-248
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• 2001

Exposure to 2-Bromopropane has been known to cause degeneration of male germ cells. However the mechanism underlying this process is poorly understood. The objective of this study was to determine whether or not the exposure of male Sprague-Dawley rats to 2-BP induces apoptosis in male germ cells. Male rats(N=3 or 4 in each group) were orally administered either with the corn oil vehicle (10 ml/kg body weight) or with 2-BP (3,500 mg/kg) once a day for 3 days. The presence of apoptosis was determined by TUNEL detection in situ and by an increase in DNA fragmentation. A low spontaneous incidence of apoptosis was observed in vehicle control animals, especially in pre-meiotic germ cells of stages I-VI and stages XII-XIV the seminiferous tubules. In 2-BP exposure rats, the incidence of apoptosis markedly increased at 4 h, reached a peak at 8 h (about 7-fold over control), and then decreased rapidly to control level by 48 h after the last administration. Although apoptosis induced by 2-BP occurred in all stages of germ cells, it was most pronounced in spermatogonia and early spermatocytes in stages I-VI and stages XII-XIV. Taken together, our results suggest that apoptosis is involved in the toxicity of testicular germ cells resulting in oligospermia or azoospermia after exposure to 2-BP.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.21-21
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• 2003

Male germ cell apoptosis has been extensively explored in rodent. In contrast, very little is known about their susceptibility to apoptosis stimuli of developing germ cell stages at the time when germ cell depletion after busulfan treatment occurs. Furthermore, it is still unanswered how spermatogonial stem cells are resistant to busulfan treatment. We examined the change of gene expression in detail using cDNA microarray analysis of mouse testis treated with busulfan. A subtoxic dose of busulfan (40mg/kg of body weight) transiently increased 228 mRNA levels among of the 8000 genes analyzed. TagMan analysis confirmed that the mRNA levels such as defensive protein, support protein, enzymatic protein, transport protein, and hormonal protein were rapidly increased. These results were re-confirmed by real-time PCR analysis. However, the expression levels of these genes induced by busulfan treatment were significantly reduced in control testis, indicating that both of male germ cells and somatic cells after busulfan treatment induces self-defense mechanism for protection of testicular cell death. Among them, we conclude that defense proteins play a key role in testis injury induced by busulfan.

• 한국발생생물학회지:발생과생식
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• 제20권1호
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• pp.11-22
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• 2016

The ultrastructures of germ cells and the functions of Leydig cells and Sertoli cells during spermatogenesis in male Kareius bicoloratus (Pleuronectidae) were investigated by electron microscope observation. Each of the well-developed Leydig cells during active maturation division and before spermiation contained an ovoid vesicular nucleus, a number of smooth endoplasmic reticula, well-developed tubular or vesicular mitochondrial cristae, and several lipid droplets in the cytoplasm. It is assumed that Leydig cells are typical steroidogenic cells showing cytological characteristics associated with male steroidogenesis. No cyclic structural changes in the Leydig cells were observed through the year. However, although no clear evidence of steroidogenesis or of any transfer of nutrients from the Sertoli cells to spermatogenic cells was observed, cyclic structural changes in the Sertoli cells were observed over the year. During the period of undischarged germ cell degeneration after spermiation, the Sertoli cells evidenced a lysosomal system associated with phagocytic function in the seminiferous lobules. In this study, the Sertoli cells function in phagocytosis and the resorption of products originating from degenerating spermatids and spermatozoa after spermiation. The spermatozoon lacks an acrosome, as have been shown in all teleost fish spermatozoa. The flagellum or sperm tail of this species evidences the typical 9+2 array of microtubules.

• 한국가금학회지
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• 제28권2호
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• pp.135-142
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• 2001

A novel sterategy has been established to determine the origin of the Primordial Germ Cells (PGCs) in avian embryos directly and the developmental fate of the PGCs for the application to Poultry biotechnology. Cells were removed from 1) the centre of area pellucida, 2) the outer of area pellucida and 3) the area opaca of the stage X blastoderm (Eyal-Giladi & Kochav, 1976). When the cells were removed from the centre of area pellucida, the mean number of circulating PGCs in blood was significantly decreased in the embryo at stage 15 (Hamburger & Hamilton, 1951) as compared to intact embryos. When the cells were replenished with donor cells, no reduction in the PGCs number was observed. The removal of cells at the outer of area pellucida or at the area opaca had no effect on the number of PGCs. In case, another set of the manipulated embryos were cultured ex vivo to the hatching and reared to the sexual maturity, the absence of germ cells and degeneration of seminiferous tubules was observed in resulting chickens derived from the blastoderm in which the cells were removed from the centre of the area pellucida. It was concluded that the avian Primordial Germ cells are originated at the center of area pellucida. Developmental ability of the cells to differentiate into somatic cells and germ cells in chimeras were analyzed. Somatic chimerism was detected as black feather attributed from donor cells. Molecular identification by use of female - specific DNA was performed. It was confirmed that the donor cells could be differentiated into chimeric body and erythrocytes. Donor cells retained the ability to differentiate into germline in chimeric gonads. More than 70% of the generated chimeras transmitted donor derived gametes to their offspring indicating that the cells at the center of area pellucida had the high ability to differentiate into germ cells. A molecular technique to identify germline chimerism has been developed by use of gene scan analysis. Strain specific DNA fragments were amplified by the method. It would be greatly contributed for the detection of germline chimerism. Mixed- sex chimeras which contained both male and female cells were produced to investigate the developmental fate of male and female cells in ovary and testes. The sex combinations of donor and recipient of the resulting chimeras were following 4 pairs; (1) chimeras (ZZ/ZZ) produced by a male donor (ZZ) and a male recipient (ZZ), (2) chimeras (ZW/ZW) produced by a female donor (ZW) and a female recipient (ZW), (3) chimeras (ZZ/ZW) Produce by a male donor (ZZ) and a female recipient (ZW), (4) chimeras (ZW/ZZ) produced by a female donor (ZW) and a male recipient (ZZ). It was found that genetically male avian germ cells could differentiate into functional ova and that genetically female germ cells can differentiate into functional spermatozoa in the gonad of the mixed- sex chimeras. An ability for introduction of exogenous DNA into the PGCs from stage X blastoderms were analyzed. Two reporter genes, SV-$\beta$gal and RSV-GFP, were introduced into the PGCs. Expression of bacterial/gal was improved by complexing DNA with liposome detectedcc in 75% of embryos at 3 days embryos. At the embryos incubated for 1 day, expression of the GFP was observed all the embryos. At day 3 of incubation, GFP was detected in about 70% of the manipulated embryos. In case of GFP, expression of the transgene was detected in 30 %e of the manipulated embryos. These results suggested that the cells is one of the most promising vectors for transgenesis. The established strategy should be very powerfull for application to poultry biotechnology.

• 한국가축번식학회지
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• 제20권1호
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• pp.43-52
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• 1996

본 연구는 생쥐의 고게정관내에 존재하는 분화단계의 정자세포를 발생단계별로 분리하여, 체외에서 단기간 배양체계를 확립하기 위하여 실시하였다. 8주령 이상된 생쥐의 정소로부터 정소막을 제거시킨 후, collagenase (1mg/ml), trypsin(2.5mg/ml)를 처리하여 곡세정관을 간질세포와 분리하여 배양액에 부유시켰다. 부유세포는 Celcep장치를 이용하여 세포크기와 밀도 차이에 의해 분화 단계별로 분리하였다. 회수된 세포의 균질성은 haematoxylin/eosin 또는 orcein으로 염색한 후, 광학현미경하에서 확인한 결과 약 85% pachytene spermatocyte와 round spermatid을 성공적으로 분리해냈다. 따라서 sedimentation velocity에 의해서 생쥐의 spermatogenic cell의 발달단계별 분리가 가능함을 알 수 있었다. 이러한 방법으로 분리된 pachytene spermatogenic cell들은 DMEM 배양액에서 6일 이상 배양한 결과 약 36%의 생존율을 보였다. 따라서, 분화단계별 정자 세포의 분리 및 배양체계의 확립은 웅성생식세포의 발생과정에 따른 생리 또는 분자생물학적 현상을 규명함은 물론 세포융합기술의 이용에 의한 형질전환동물 생산에의 응용을 통해 가축에 있어서의 형질전환 생산효율의 개선에 기여할 수 있으리라 사료된다.