• Korean Journal of Animal Reproduction
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• v.25 no.2
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• pp.101-111
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• 2001

The present study was conducted to develop an in vitro culture system that would support bovine follicle growth from preantral to antral stage, oocyte maturation, fertilization, and embryonic development. Bovine preantral follicles (150$\pm$1.2 ${\mu}{\textrm}{m}$) surrounded by theca cell were isolated ezymatically and mechanically from ovarian cortical slides in Leibovitz L-l5 medium containing 1 mg/$m\ell$ collagenase and 0.2 mg/$m\ell$ DNase I and cultured for 25 days in the presence of different concentrations of bovine FSH and LH in $\alpha$MEM medium. The survival and growth rates of follicles cultured in the presence of FSH (10~150 ng/$m\ell$) were significantly higher than those of control group (P ＜ 0.001), but no significant differences were observed in survival and growth rates of follicles between the LH treatment groups (1~125 ng/$m\ell$) and the control. The survival (40%) and growth (244 $\pm$ 0.5 $\mu\textrm{g}$) of follicles cultured with FSH (90 ng/$m\ell$) and LH (25 ng/$m\ell$) were higher than those of control (25%, 160 $\pm$1.0 $\mu\textrm{g}$). Finally, 50% percent of healthy antral follicles were obtained, and almost 60% of them has complete meiotic division with 1st polar body (18.1%) and 10.0% have developed to the cleaved embryo and blastocyst stage. These results suggest that bovine preantral follicle with intact theca cell can grow to the antral stage using these culture conditions, and that oocytes from in vitro-matured bovine preantral follicle may acquire meiotic competence and can undergo fertilization and development.

• Journal of Embryo Transfer
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• v.13 no.3
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• pp.245-249
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• 1998

The purpose of this study was to evaluate the effects of growth factors such as epidermal growth factor (EGF) and insulin-like growth factor-1 (IGF-1) on maturation of bovine follicular oocytes in vitro. Oocytes were recovered from the ovaries of slaughtered Hanwoos. The oocytes were matured in TCM 199 at 39$^{\circ}C$, 5% $CO_2$ in air. Growth factors were added to maturation medium as follows: control (no serum), EGF (10ng/m1, 50ng/ml or 100ng/m1), IGF-1 (100ng/m1) and EGF (50ng/ml) + IGF-1 (100ng/m1). The oocytes were placed onto a slide and stained with aceto-orcein dye. Nuclear maturation was evaluated and classified as germinal vesicle breakdown (GVBD), metaphase-I (MI) or metaphase-ll(Mll). Maturation rates were 37.9% (control), 45.8% (EGF, 10ng/m1), 55.8% (EGF, 50ng/ml), 44.4% (EGF, 100ng/m1), 46.7% (IGF-1, 100ng/m1) and 67.0% (IGF-1+EGF). The highest group developed to Mll stage was IGF-1+EGF treatment group (p<0.05). Therefore, nuclear maturation of bovine oocytes were affected by both of growth factors, and it seems to have a mutual activity between them.

• Development and Reproduction
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• v.6 no.2
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• pp.89-96
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• 2002

The present study was conducted to elucidate genes involved in the primordial-primary follicular transition. By using suppression subtractive hybridization, day1- and day5-subtracted cDNA libraries were obtained with the forward and reverse subtraction method, respectively. In toto, 357 clones were sequenced and analyzed by BLAST and RIKEN program. Sequences of 330 clones significantly matched database entries while 27 clones were novel. Forty-two and 47 genes with known functions were different between day1 and day5 ovaries. Four genes, GDF8, lats2, septin2, and wee1, from the day1 subtracted cDNA library, and 6 genes, HSP84, laminin2, MATER, MTi7, PTP, and wrn, from day5-subtracted cDNA library were chosen, and their differential expression was evaluated using RNAs from whole ovaries as well as captured primordial and primary follicles by laser captured microdissection. Results from the present study would provide insight for the future study on the mechanisms involved in primordial-primary follicle transition in the mouse in addition to the human ovary.

• Clinical and Experimental Reproductive Medicine
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• v.36 no.4
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• pp.265-274
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• 2009

Objective: MicroRNAs (miR) are known to repress target genes at post-transcriptional level and play important roles in development and maturation of cell. However, the expression profiles of miR during ovarian follicle maturation have not been fully elucidated. Here, we designed this study to investigate the expression profiles of miR in oocytes and granulose cells (G-cells) after in vitro culture according to gonadotropins and adding hCG. Methods: Ovaries from 12-day-old mice (C57BL6) were removed and preantral follicles were isolated and cultured in $20\;{\mu}L$-drop of culture media with supplementation of either rFSH, rLH, or rFSH+rLH. After their full maturation, follicles were incubated with rhCG and rEGF. RNA was isolated from oocytes and G-cells, and real-time PCR were performed with primers of miR known to be expressed in the mouse ovary (mmu-miR-16, -miR-27a, -miR-126, -miR-721). Results: FSH+LH group showed the highest ovulation and MII rates among gonadotropin groups. The profiles of miRs in oocytes and G-cells differed according to gonadotropin groups and adding hCG. The profiles of miRs showed divergent changes between oocytes and G-cells. Conclusion: miR expression profiles are altered by gonadotropins and supplementation of hCG during in vitro maturation of murine follicles. Target gene study must be necessary to validate these findings.

• Journal of Radiation Protection and Research
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• v.23 no.2
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• pp.89-96
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• 1998

To assess the radioprotective effects of follicle stimulating hormone (FSH) on ovarian follicles, 3 week-old female mice were irradiated with 8.33 Gy of ${\gamma}$-ray (group R) and followed by 5 IU ip-injection of FSH (group RF). For control groups, 5 IU of saline (group C) or 5 IU of FSH (group F) was ip-injected. Ovaries were collected 0h, 6h, 12h, 14, 2d, 4d, and 8d after irradiation or saline/FSH injection, and followed by fixation in neutral buffered formalin for routine histochemistry. Immunohistochemistry was used to assess the status of follicles and DNA fragmentation was analyzed by agarose gel electrophoresis for total DNA. Staining specific for apoptotic follicles showed high intensity at 6h and 12h in group R and RF On the other hand, staining specific for proliferating follicles showed noticeably high intensity at 8d in group R and Rf. DNA fragmentation of 185bp increased with time in all experimental groups. Especially 370bp appeared at 6h in group R, then disappeared after 1d. In case of group RF, it appeared at 12h and disappeared after 1d. From the above results, the irradiated antral follicles become completely disappeared from 4d to 8d, and then new follicles started to grow again at 8d. FSH had delaying or suppressing effects on follicular atresia after irradiation. In addition, it became clear that radiation-induced follicular atresia was mediated by granulosa cell apoptosis.

• The Korean Journal of Zoology
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• v.36 no.2
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• pp.304-318
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• 1993

1991년 8월부터 그이듬해 7월까지 채취된 무지개 송어(Oncorhvnchus mykiu) 난모세포의발달 단계를 이해하기 위하여 광필 및 전자현미경을 이용하여 본 각구를 실시하였다. 건국 대학교 축산대학 양수.장에서 수온이 14-16$^{\circ}C$이고 용존산소량이 7.6 $\pm$ 0.3ppm. PH 5.8 $\pm$ 0.2인 자연채광 상태인 1개의 10m3 탱크에서 N R.C. 사양표준에 준한 펠렛트 배합사료를 급여하여 연중 사육중인 체중 700-1,2009의 한복새끼인 무지개 송어 암컷 120마리를 공시희.로 이용 하였다. LPO(late perinucleolus oocyte), EMO(early maturing oocyte) 단계에서 과립막 세포와 협막세포와 같은 난포막 세포는 단층구조로 부터 입 방형구조로 변화되었고. 완전한 성장, 성숙 및 과숙기에 방사대(Eons rsdiat3)에 있는 pore canals의 입구가 봉쇄되었다. 방사대는 맨바깥목에 균일하면서 점은 두께의 막과 나선형의 두꺼운 복의 2개의 막으로 구성되어 있으며. 성숙기에 있는 난모세포에는 수초 및 자갈에 붙을 수 있는 온수성 어종 보다 상대적으로 얇은 점액성의 막이 그 주위를 둘러싸고 있다. 난모세포가 성장함에 따라 세포질 주변부 및 임립등 세포내에 막대기 형태의 미토콘드리아와 비대해진 내형질세강의 육가 급증하였다. 전자밀도가 높은 소포는 방사대에 인접한 난세포질 주변부에 많이 존재하며. 이는 성장중인 방사대의 pore Canals을 통해서 간으로 부터 합성된 단백질과 탄수화물을 수송하는 것과 밀접한 관계가 있는 것으로 사료된다. 자연적인 조건하에서 fP포막은 난형성 및 이에 영향을 미치는 성호르몬의 발달에 충분한 대르몬을 계절에 따라 분비시키는 데에 커다란 영향을 미치는 것으로 나타났다.

• Development and Reproduction
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• v.5 no.2
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• pp.115-122
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• 2001

Production of a mature oocyte is a complex process that requires the close association between oocyte and follicular cells. The present study was conducted to investigate the difference between oocytes with and without close junctional communication with cumulus cells and the involvement of two connexins(CXs) in the interactions. Follicles at different sizes(small: 200～400 ㎛; large:>450 ㎛) were mechanically isolated from PMSG-primed mouse ovaries, and punctured to get cumulus-oocyte complex(COC). Oocytes were released themselves(denuded), with partially attached(partial), or with tightly attached(intact) cumulus cells. Maturation and fertilization capacity of the COCs were measured. Expression of CX 37 and CX 43 was examined by RT-PCR and in situ hybridization. The ratio between intact COC and denude/partial oocytes was 30％(SI) and 70％(SPD) in small follicles, while 55％(LI) and 45％(LPD) in large follicles, respectively. Maturation and fertilization rates of the released oocytes were similar among SI, LPD, LI groups, but those were significantly lower in SPD oocytes. In oocytes, CX 37 was the major CX and CX 43 was not expressed, whereas in the cumulus cells, CX 43 was the major, and CX 37 was the next. Results of the present study suggest that 1) immature oocytes from small follicles with intact cell-to-cell communication with cumulus have the similar quality to that of the oocytes from larger follicles, 2) gap junction between oocyte and cumulus cells may be the heterotypic channel, and 3) we could not explain the difference in the cell-to-cell communication between intact and partial/denuded COCs through the expression of the two CXs.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.2
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• pp.111-118
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• 2008

Objective: The purpose of the present study was to examine the hormonal regulation of RGS-2 in the rat ovary. Methods: Immature rats were injected with 10 IU of PMSG to induce multiple growth of preovulatory follicles and 10 IU of hCG to induce ovulation. Northern blot analysis performed for gene expression and in situ hybridization performed for mRNA localization. Results: Northern blot analysis revealed that pregnant mare's serum gonadotropin (PMSG) treatment did not affect RGS-2 mRNA levels. In contrast, human chorionic gonadotropin (hCG) treatment of PMSG-primed rats resulted in an increase in RGS-2 expression within $1{\sim}3\;h$. The major cell-types expressing RGS-2 mRNA were oocytes regardless of follicle size. Interestingly, hCG treatment caused the stimulation of RGS-2 gene expression in granulosa cells of preovulatory and growing follicles. In contrast, cell types expressing RGS-2 protein were theca cells regardless of hCG treatment. Like in vivo, treatment of preovulatory granulosa cells with LH in vitro stimulated RGS-2 levels within 1 h. Interestingly, GnRH antagonist II enhanced the stimulatory action of LH. Conclusion: The present study demonstrates the LH/hCG induction of RGS-2 in preovulatory granulosa cells and suggests a role of RGS-2 in Gq protein signaling pathway during ovulation.

• Journal of Animal Science and Technology
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• v.51 no.5
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• pp.413-420
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• 2009

The research has been aimed to investigate the effect of different sera including fetal bovine serum (FBS), male bovine serum (MS), female bovine serum (FS), and castrated-male bovine serum (C-MS) on cell proliferation, follicular maturation and ovulation in vitro. Established cell lines and primary cells were cultured in the culture media supplemented with different sera and cells proliferation was observed by cell counting and MTT assay. The results indicated that cell proliferation was significantly different for different serum source. Proliferation of bovine and human myogenic satellite cells was highest in MS. In contrast, proliferation of breast cancer cells and immune cells were the highest in FS and FBS, respectively. There was no difference in the rate of follicular growth, whereas the rate of ovulation was higher in FBS and C-MS. Finally, the wound healing effect and cell proliferation of 3T3-L1 cells showed that wound healing was fastest in FS and cell proliferation was higher in MS. These results suggest the importance of an optimal serum selection in the experiments involving cell culture system, and gender-specific Hanwoo sera may be used as a substitute to FBS.

• Proceedings of the KSAR Conference
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• 2002.06a
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• pp.44-44
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• 2002

본 연구는 돼지의 미성숙 난포란을 체외에서 성숙, 수정시킨 후, 생산된 체외 수정란을 NCSU 23 체외배양액에 항산화제(NAC, ebselen 및 glutathione) 와 성장 인자 (EGF, PDGF)의 첨가가 돼지 체외 수정란의 체외 발육에 미치는 영향을 검토하였다. NAC을 0, 0.5, 1.0 및 2.0 mL 첨가하여 체외배양한 결과, 상실배기 이상 발육된 체외발육성적이 1.0mL과 2.0 mM 첨가구가 여타구보다 유의하게 높은 체외발육성적을 나타냈다.(p〈0.05). (중략)