• 한국가축번식학회지
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• 제19권3호
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• pp.205-216
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• 1995

Microtubules와 micrfilaments는 포유동물 난자이 주요한 세포 구조물들로, 이들은 난자의 성숙, 수정 및 배발달시 핵질의 이동과 세포질 분열에 직접 관여하는 것으로 알려져 왔다. 난자내 세포구조물의 정확한 움직임은 정상적인 배 발달을 위해 필수적이다. Microtubules는 $\alpha$, $\beta$- bubulin이 서로 연결되어 이루어져 있으며, 수정시 웅성.자성전핵 움직임과 세포분열시, 유사 및 감수분열시 그 역할을 한다. 생쥐를 제외한 대부분의 동물에서 microbubules의 역할은 수정시 정자가 centrosome을 난자내로 이전하여 sperm aster를 형성함으로써 시작된다고 보고되고 있다. 따라서 정자의 도움없이 배발달이 일어나는 단위발생시 microbubules의 형성은 연구들 사이에 흥미로운 연구대상이 되고 있다. 한편 microfilaments는 세포분열시 세포질을 분할하는 기계적인 역할을 하는 것으로 알려져 있으며, 최근 생쥐 난자에서는 정자의 난자내 융합과 웅성 및 자성 전핵의 이동에 관여한다고 보고되고 있다. 포유동물 난자의 체외성숙, 체외수정을 유도할 때 여러 가지 비정상적인 핵움직임과 세포분열이 관찰되어지고, 낮은 배발달율이 보고되고 있는데, 최근 연구자들은 세포구조물, 즉 microtubules와 microfilaments의 비정상적인 역할에서 기인한다고 보고 있다. 따라서 포유동물 난자의 성숙.수정 및 단위발생시 세포구조물의 움직임과 역할 및 상호관계에 대한 정확한 이해는 체외수정율 및 배발달 향상에 중요한 기초자료로 이용되리라고 본다.

• 한국발생생물학회지:발생과생식
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• 제20권4호
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• pp.359-365
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• 2016

Intact germinal vesicle (GV) arrest and release are essential for maintaining the fertility of mammals inducing human. Intact germinal vesicle release, maturation of oocytes is maintained by very complex procedures along with folliculogenesis and is a critical step for embryonic development. Cyclic guanosine monophosphate (cGMP) has been suggested a key factor for meiotic arrest but so far its mechanisms are controversy. In this study we examine the effects of cGMP on germinal vesicle breakdown in cumulus-enclosed oocytes and denuded oocytes. Spontaneous maturation was inhibited by a cGMP agonist, 8-Br-cGMP with concentration dependent manners both in cumulus-enclosed oocytes and denuded oocytes. The inhibitory effect was more severe in denuded oocytes than cumulus-enclosed oocytes. The Rp-8-Br-cGMP and Rp-pCPT-8-Br-cGMP did not severely block GVB compared to 8-Br-cGMP. The spontaneous GVB inhibitory effects were different by the existence of cumulus. Based on them it is suggested that the cumulus modulates the role of cGMP in GV arrest.

• 한국발생생물학회지:발생과생식
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• 제2권1호
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• pp.9-20
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• 1998

Phospholipase C (PLC)는 다양한 세포주에서 세포내 신호전달에 중요한 역할을 한다고 알려져 있으나, 생쥐 난자성숙 과정과 착성전 배아발생 과정에서 PLC의 역할과 발현은 아직 연구된 바 없다. 본 연구에서는 난자성숙과 착상전 배아발생 과정에서 생쥐의 PLC \beta 1과 \gamma 1의 유전자 발현을 조사하기 위하여 한 개의 난자 혹은 배아에서 추출된 total RNA를 사용하여 경쟁적 RT-PCR 방법으로 mRNA를 정량하였다. PLC \gamma 1의 유전자 발현을 조사하기 위하여 한 개의 난자 혹은 배아에서 추출된 total RNA를 사용하여 경쟁적 RT-PCR 방법으로 mRNA를 정량하였다. PLC \gamma 1의 유전자는 전혀 발현하지 않았다. 수정후 PLC \betta 1과 \gamma 1의 유전자 발현은 상실기 배아에서 증가하기 시작하여 포배기 배아에서는 현저히 증가하였다. 난자성숙과 착상전 배아발생 과정에서 protein kinase C(PKC) 신호전달체게에 의한 PLC의 역할을 조사하기 위하여 PKC의 억제제인 sphingosin, PKC의 촉진제인 $diC_{8}$, 그리고 PLC의 억제제인 U73122의 효과를 조사하였다. Spihingosine은 처리후 1시간 이내에 대조군에 비해 20% 정도의 난자성숙을 촉지하였으나 U73122는 유효한 효과를 보이지 않았다. U73122는 상실기 배아의 compaction을 억제하였으나 $diC_{8}$에 의하여 부분적으로 극복되었다. 이상의 결과는 PLC \beta 1과 \gamma 1 유전자가 생쥐의 착상전 발생단계에서 특이젖으로 발현하고 있으며, 난자성숙과 착상전 초기배아에서 PKC-PLC 신호전달체계가 관여하고 있으리라 사료된다.

• 한국수정란이식학회지
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• 제30권4호
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• pp.319-325
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• 2015

Gangliosides exist in glycosphingolipid-enriched domains on the cell membrane and regulate various functions such as adhesion, differentiation, and receptor signaling. Ganglioside GM3 by ST3GAL5 enzyme provides an essential function in the biosynthesis of more complex ganglio-series gangliosides. However, the role of gangliosides GM3 in porcine oocytes during in vitro maturation and early embryo development stage has not yet understood clear. Therefore, we examined ganglioside GM3 expression patterns under apoptosis stress during maturation and preimplantation development of porcine oocytes and embryos. First, porcine oocytes cultured in the NCSU-23 medium for 44 h after $H_2O_2$ treated groups (0.01, 0.1, 1 mM). After completion of meiotic maturation, the proportion MII (44 h) was significantly different among control and the H2O2 treated groups ($76.8{\pm}0.3$ vs $69.1{\pm}0.4$; 0.01 mM, $55.7{\pm}1.0$; 0.1 mM, $38.2{\pm}1.6%$; 1 mM, P<0.05). The expressions of ST3GAL5 in $H_2O_2$ treated groups were gradually decreased compared with control group. Next, changes of ST3GAL5 expression patterns were detected by using immunofluorescene (IF) staining during preimplantation development until blastocyst. As a result, we confirmed that the expressions of ST3GAL5 in cleaving embryos were gradually decreased (P<0.05) according to the early embryo development progress. Based on these results, we suggest that the ganglioside GM3 was used to the marker as pro-apoptotic factor in porcine oocyte of maturation and early embryo production in vitro, respectively. Furthermore, our findings will be helpful for better understanding the basic mechanism of gangliosides GM3 regulating in oocyte maturation and early embryonic development of porcine in vitro.

• Clinical and Experimental Reproductive Medicine
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• 제24권1호
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• pp.1-11
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• 1997

It is well known that the zona pellucidae of mouse oocytes become "hardened" when they are allowed to mature in vitro in the absence of serum components. To see if oocytes already undergone meiotic resumption in vivo exhibit similar zona hardening, hardening of ZP of cumulus-enclosed oocytes(CEOs) was examined after culture in vitro since their release from follicles various hours after hCG injection. When CEOs matured in vivo for 3h or longer were subjected to culture in vitro for 14h with BSA alone, zona hardening was significantly reduced compared to those cultured in vitro from the begining of maturation. However, when CEOs matured in vivo for 5h were freed from cumulus cells and then cultured in vitro with BSA alone, little reduction of zona hardening was observed. Preincubation of CEOs for 5h with fetuin, one of the well known inhibitor of in vitro zone hardening, did not prevent zona hardening during its subsequent culture of CEOs for 14h without fetuin. However, when CEOs precultured with both fetuin and PMSG for 5h and then further cultured with BSA alone for 14h, zona hardening was dramatically reduced. Under these conditions, the expansion of cumulus cell was observed. In addition, CEOs cultured with both BSA and dbcAMP to prevent their meiotic resumption showed a significant increase of zona hardening. Whether the observed zona hardening was correlated with the conversion of ZP2 to $ZP2_{f}$ was examined. Zona pellucida, isolated from CEOs matured for 5h in vivo and then further cultured with BSA alone was subjected to SDS-PAGE. Most of ZP2 molecules from these CEOs did not undergo conversion from ZP2 to $ZP2_{f}$. From these results, it is concluded that CEOs undergone meiotic resumption in vivo do not exhibit zona hardening when they were subsequently cultured in vitro without serum components. It appears that cumulus cells play an important role in this phenomenon.

• Clinical and Experimental Reproductive Medicine
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• 제28권2호
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• pp.111-120
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• 2001

Objective: To verify the expression of leptin receptor (OB-R) in oocytes and preimplantation embryos, the involvement of mitogen activated protein kinase (MAPK or Erk1/2) in the leptin signaling, and effect of leptin on the oocyte maturation in mice. Method: RT-PCR analysis of OB-R was conducted in germinal vesicle (GV)-intact and MII stage oocytes, and 1, 2, 8-cell embryos and blastocysts. Germinal vesicle breakdown (GVB), polar body extrusion, monitored in the presence or absence of leptin ($1{\mu}M$). Following the leptin treatment, temporal changes in MAPK activity were verified by immunoprecipitation and in vitro kinase assay in MII oocytes. Results: The expression of OB-R mRNA was found in GV and MII oocyte but not in the embryos. MAPK activity of the MII oocytes was significantly increased by brief incubation in the HTF supplemented with leptin ($1{\mu}M$). Priming of PD098059, a MEK inhibitor to leptin treatment attenuated the activation of MAPK by leptin in MII oocytes. Following 24 hrs of culture of the GV oocytes, leptin significant increased the GVB and 1 st polar body extrusion. Conclusion: This result suggested that functional interaction between leptin and OB-R resulted in potentiation of MAPK (Erk1/2) activity in MII oocytes through MEK activation and that leptin might be a local regulator of meiotic maturation of the mouse oocytes.

• 한국수정란이식학회지
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• 제10권1호
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• pp.45-51
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• 1995

In order to determine the optimum condition and timing for in vitro maturation of oocytes to metaphase of meiosis II (M II), the immatured follicular oocytes were recovered by puncturing the large(1.0~1.5 mm in diameter) and small(<1.0 mm in diameter) follicles in the ovaries of rabbits treated intramuscularly with a single dose of 100 TU PMSG 68 hours previously. The follicular oocytes were classified into three grades by the attachment of cumulus cells. The Grade I and II follicular oocytes from large follicles were cultured in BO-DM medium with 10% FCS, 35 $\mu$g /nl of FSH, 10 $\mu$g /ml of LH and 1 $\mu$g /ml of estradiol-17$\beta$ at 39t in a 5% $CO_2$ incubator for 11 to 23 hours. In 3 hours interval during the culture period, the oocytes were harvested and their cumulus cells were removed with hyaluronidase. The denuded oocytes were stained with Hoechst 33342 dye and their meiotic status and extrusion of the first polar body (PB) were examined under a fluorescence microscope. Also the fragmentation of the first PB and the distance between the first PB and nucleus were examined. The results obtained were as follows: 1. The mean recovery rate of follicular oocytes from the large and small follicles was 59. 9 and 31.3%, respectively. The mean number of oocytes recovered per rabbit and the Grade I percentage were 14.6 and 94.4% in large follicles, but 2.1 and 61.1% in small follicles, respectively. All the parameters examined were different significantly (p<0.05) between both the folliclular size. 2. Most of the follicular oocytes(86.8%) were matured in vitro to M II phase in 14 hours in Grade I oocytes, but the significantly(p<0.05) less oocytes(45.5%) were matured in Grade II oocytes. 3. The first PB was extruded in most of the oocytes(94.7%) in 14 hours of culture with the fragmentation rate of 29.6%, but the fragmentation rate of the first PB increased significantly (p<0.05) as the culture period for maturation was longer to 20 hours(63.5%). 4. The distance between the first PB and nucleus was increased linearly (p<0.05) as the maturation time passed from 14(7.1$\mu$rn) to 23 hours(58.4$\mu$m). 5. From the above results it was concluded that the optimum time for in vitro maturation culture might be 14 hours in the follicular oocytes from rabbit primed with PMSG for 68 hours, expecially when these follicular oocytes were used for recipient cytoplasms in embryo cloning.

• Asian-Australasian Journal of Animal Sciences
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• 제15권4호
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• pp.485-493
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• 2002

Different factors may affect the sensitivity of porcine oocytes during cryopreservation. The effect of two methods (cooling and vitrification), four cryoprotectants [glycerol (GLY), 1, 2-propanediol (PROH), dimethyl sulfoxide (DMSO) or ethylene glycol (EG)] and two vitrification media (1 M sucrose (SUC)+8 M EG; 8 M EG) on the developmental capacity of porcine oocytes at the germinal vesicle (GV) stage or after IVM at the metaphase II (M II) stage were examined. Survival was assessed by FDA staining, maturation and cleavage following IVF and IVC. A toxicity test for different cryoprotectants (GLY, PROH, DMSO, EG) was conducted at room temperature before cooling. GV and M II-oocytes were equilibrated stepwise in 1.5 M cryoprotectant and diluted out in sucrose. The survival rate of GV-oocytes in the GLY group was significantly lower (82%, p<0.01) than that of the other group (92 to 95%). The EG group achieved a significantly higher maturation rate (84%, p<0.05) but a lower cleavage rate (34%, p<0.01) than the DMSO group and the controls. For M II-oocytes, the survival rates for all groups were 95 to 99% and the cleavage rate of the GLY group was lower than the PROH-group (21 vs 43%, p<0.01). After cooling to $10^{\circ}C$, the survival rates of GV-oocytes in the cryoprotectant groups were 34 to 51%, however, the maturation rates of these oocytes were low (1%) and none developed after IVF. For M II-oocytes, the EG group showed a significantly higher survival rate than those of the other cryoprotectant groups (40% vs 23-26%, p<0.05) and the cleavage rates of PROH, DMSO and EG group reached only 1 to 2%. For a toxicity test of different vitrification media, GV and M II-oocytes were equilibrated stepwise in 100% 8 M EG (group 1) and 1 M SUC + 8 M EG (group 2) or equilibrated in sucrose and then in 8 M EG (SUC+8 M EG, group 3). For GV-oocytes, the survival, maturation and cleavage rates of Group 1 were significantly lower than those in group 2, 3 and control group (p<0.05). For M II-oocytes, there were no differences in survival, maturation and cleavage rates between groups. After vitrification, the survival rates of GV and M II-oocytes in group 2 and 3 were similarly low (4-9%) and none of them matured nor cleaved after in vitro maturation, fertilization and culture. In conclusion, porcine GV and M II-oocytes do not seem to be damaged by a variety of cryoprotectants tested, but will succumb to a temperature decrease to $10^{\circ}C$ or to the process of vitrification, regardless of the cryoprotectant used.

• 대한의생명과학회지
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• 제11권4호
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• pp.545-553
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• 2005

The present study provides descriptions of the cellular associations of the seminiferous epithelium cycle in the Crocidura shantungensis. The cycle of the seminiferous epithelium was divided into 14 stages, and developing spermatids were subdivided into 15 steps. The Golgi phase occurs the first two steps, and the cap phase had the next four consecutive steps. The acrosomal and maturation phases were consisted of steps $7\~14$, and the remaining one step consisted the spermiation phase. The Ad type of spermatogonia was observed whole stages, and Ap, In and B spermatogonia were observed from stage II to stage VI. The preleptotene, leptotene and zygotene of primary spermatocytes were observed from VII to XIV stages, and pachytene spermatocyte was observed from I to XII stages. The diplotene spermatocyte was observed XIII stages, and meiotic figures and secondary spermatocytes were observed stage XIV. Our results provide the foundation for a variety of future studies of the spermiogenesis of C. shantungensis.

• 한국동물학회지
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• 제37권2호
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• pp.174-181
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• 1994

3 종의 한국산개구리를 사용하여 여포들이 생성하는 스테로이드와 난자의 성숙능이 번식기 근처에서 어떻게 변하는가를 조사하였다. 개구리의 여포를 생체외 배양하면서 이들이 뇌하수체추출물(frog pituitary homogenate, FPH) 혹은 CAMP의 자극으로 생성하는 progesterone(Pa)과 testosterone(T)의 양을 측정하여 이로부터 P4yT의 비율을 구하였으며 여포난자들이 FPH. P4 혹은 12-0-tetrsdecanoyl phorbol-13-acetate(TPA)에 반응하여 성숙을 일으키는 시기를 조사하였다. 북방산개구리의 여포난자는 11월 부터 호르몬에 반응하여 성숙을 일으켰으며 2월에 PJT의 비율이 급격히 증가하였다 참개구리는 5월에 가서of PJT의 비율이 현저히 증가하고 FPH에 반응하여 성숙을 일으켰다. 그러나 P4에 의한 난자성숙은 3월부터 시작하였다 옴개구리는 7월에 P4/T 비율의 증가가 있었으며 이때부터 또한 TPA에 반응하여 난자의 성숙을 일으켰다 따라서 3종의 개구리에서 모두 각각의 번식기 근처에서 PJT의 비가 급격히 증가하고 또한 성숙능이 생긴다는 것을 알 수있었다.