• Clinical and Experimental Reproductive Medicine
• /
• 제39권2호
• /
• pp.58-67
• /
• 2012

Objective: Previously, we identified that transketolase (Tkt), an important enzyme in the pentose phosphate pathway, is highly expressed at 2 hours of spontaneous maturation in oocytes. Therefore, this study was performed to determine the function of Tkt in meiotic cell cycle regulation, especially at the point of germinal vesicle breakdown (GVBD). Methods: We evaluated the loss-of-function of Tkt by microinjecting Tkt double-stranded RNAs (dsRNAs) into germinal vesicle-stage oocytes, and the oocytes were cultured in vitro to evaluate phenotypic changes during oocyte maturation. In addition to maturation rates, meiotic spindle and chromosome rearrangements, and changes in expression of other enzymes in the pentose phosphate pathway were determined after Tkt RNA interference (RNAi). Results: Despite the complete and specific knockdown of Tkt expression, GVBD occurred and meiosis was arrested at the metaphase I (MI) stage. The arrested oocytes exhibited spindle loss, chromosomal aggregation, and declined maturation promoting factor and mitogen-activated protein kinase activities. The modified expression of two enzymes in the pentose phosphate pathway, Prps1 and Rbks, after Tkt RNAi and decreased maturation rates were amended when ribose-5-phosphate was supplemented in the culture medium, suggesting that the Tkt and pentose phosphate pathway are important for the maturation process. Conclusion: We concluded that Tkt and its associated pentose phosphate pathway play an important role in the MI-MII transition of the oocytes' meiotic cell cycle, but not in the process of GVBD.

• Clinical and Experimental Reproductive Medicine
• /
• 제48권2호
• /
• pp.163-173
• /
• 2021

Objective: This study aimed to characterize a validated model for predicting oocyte retrieval in controlled ovarian stimulation (COS) and to construct model-based nomograms for assistance in clinical decision-making regarding the gonadotropin protocol and dose. Methods: This observational, retrospective, cohort study included 636 women with primary unexplained infertility and a normal menstrual cycle who were attempting assisted reproductive therapy for the first time. The enrolled women were split into an index group (n=497) for model building and a validation group (n=139). The primary outcome was absolute oocyte count. The dose-response relationship was tested using modified Poisson, negative binomial, hybrid Poisson-E_max, and linear models. The validation group was similarly analyzed, and its results were compared to that of the index group. Results: The Poisson model with the log-link function demonstrated superior predictive performance and precision (Akaike information criterion, 2,704; λ=8.27; relative standard error (λ)=2.02%). The covariate analysis included women's age (p<0.001), antral follicle count (p<0.001), basal follicle-stimulating hormone level (p<0.001), gonadotropin dose (p=0.042), and protocol type (p=0.002 and p<0.001 for short and antagonist protocols, respectively). The estimates from 500 bootstrap samples were close to those of the original model. The validation group showed model assessment metrics comparable to the index model. Based on the fitted model, a static nomogram was built to improve visualization. In addition, a dynamic electronic tool was created for convenience of use. Conclusion: Based on our validated model, nomograms were constructed to help clinicians individualize the stimulation protocol and gonadotropin doses in COS cycles.

• Clinical and Experimental Reproductive Medicine
• /
• 제48권4호
• /
• pp.347-351
• /
• 2021

Objective: We investigated the impact of vitamin D₃ (VD3) supplementation during mouse preantral follicle culture in vitro and the mRNA expression of 25-hydroxylase (CYP2R1), 1-alpha-hydroxylase (CYP27B1), and vitamin D receptor (VDR) in mouse ovarian follicles at different stages. Methods: Preantral follicles were retrieved from 39 BDF1 mice (7-8 weeks old) and then cultured in vitro for 12 days under VD3 supplementation (0, 25, and 50 pg/mL). Follicular development and the final oocyte acquisition were assessed. Preantral follicles were retrieved from 15 other BDF1 mice (7-8 weeks old) and cultured without VD3 supplementation. Three stages of mouse ovarian follicles were obtained (preantral, antral, and ruptured follicles). Total RNA was extracted from the pooled cells (from 20 follicles at each stage), and then reverse transcriptase-polymerase chain reaction was performed to identify mRNA for CYP2R1, CYP27B1, and VDR. Results: The survival of preantral follicles, rates of antrum formation and ruptured follicles (per initiated follicle) and the number of total or mature oocytes were all comparable among the three groups. Both CYP2R1 and CYP27B1 were expressed in antral and ruptured follicles, but not in preantral follicles. VDR was expressed in all three follicular stages. Conclusion: VD3 supplementation in vitro (25 or 50 pg/mL) did not enhance mouse follicular development or final oocyte acquisition. Follicular stage-specific expression of CYP2R1, CYP27B1, and VDR was observed.

• 한국발생생물학회지:발생과생식
• /
• 제15권3호
• /
• pp.197-204
• /
• 2011

Egg activation is a crucial step that initiates embryo development upon breaking the meiotic arrest. In mammalian, egg activation is accomplished by fusion with sperm, which induces the repeated intracellular $Ca^{2+}$- increases ($[Ca^{2+}]_i$ oscillation). Researches in mammals support the view of the $[Ca^{2+}]_i$ oscillation and egg activation is triggered by a protein factor from sperm that causes $[Ca^{2+}]_i$ release from endoplasmic reticulum, intracellular $[Ca^{2+}]_i$ store, by persistently activation of phosphoinositide pathway. It represents that the sperm factor generates production of inositol trisphosphate ($IP_3$). Recently a sperm specific form of phospholipase C zeta, referred to as PLCZ was identified. In this paper, we confer the evidence that PLCZ represent the sperm factor that induces $[Ca^{2+}]_i$ oscillation and egg activation and discuss the correlation of PLCZ and infertility.

• BMB Reports
• /
• 제35권6호
• /
• pp.604-608
• /
• 2002

The effects of progesterone on the acrosome reaction, as well as the effects of RU486 on the progesterone-induced acrosome reaction in capacitated boar spermatozoa, were investigated. Progesterone, a major steroid that is secreted by the cumulus cells of oocyte, clearly induced the acrosome reaction in a dose-dependent manner in capacitated boar spermatozoa, even though it failed to show similar effects in non-capacitated spermatozoa. RU486, a potent antiprogestin, significantly reduced the effects of progesterone on the progesterone-induced acrosome reaction; however, when treated alone, it showed no inhibitory effects on the acrosome reaction. The inhibitory effects of RU486 were also shown to be dose-dependent. These results imply that in addition to the well-known inducer of the acrosome reaction, zona pellucida, progesterone can also induce the acrosome reaction through its specific receptors on spermatozoa after the spermatozoa undergo capacitation.

• 한국동물학회지
• /
• 제38권2호
• /
• pp.212-219
• /
• 1995

Through the histolosical observation of ovary in the nine species of the genus Cobitis, we found that specific adhesive membranes were attached to the outer zone radials during the vitellosenesis. These adhesive membranes could be classified into four forms as follows: 1) granular form of Colitis lutheri, C. striate, and C. sinensis, 2) villous form of C. longicorpus, C. konensis koreensis, C. k. pumilus, and C. granoei, 3) saw-like form of C. rotundicaudata, and 4) filamentous form of C. chou. The various forms of adhesive membrane of egg in the cobitid fishes are showed a species specificitv with reference to their habitats and spawning property.

• 대한생식의학회:학술대회논문집
• /
• 대한불임학회 2006년도 The 5th Biannual Meeting of Pacific Rim Society for Fertility and Sterility
• /
• pp.161.1-161.1
• /
• 2006

• 한국동물번식학회:학술대회논문집
• /
• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
• /
• pp.51-51
• /
• 2003

Oct-4 is a maternally expressed octamer-binding protein encoded by the murine Oct-4 gene. It is present in unfertilized oocytes, but also in the inner cell mass and in primordial germ cells. In addition, Oct-4 is the first transcrition factor described that is specific for the blastocysts stage bovine embryos. The spatial and temporal expression patterns were further determined using Immunohistochemistry. With this technique Oct-4 protein expression is detected in the oocyte, in the blastocyst. After pregnancy Oct-4 expression is restricted ovary and placental tissue. Therefore Oct-4 is a transcription factor that is specifically expressed in cells participating in the pregnancy of Korean native cattle. These result suggest that Oct-4 localization and expression may contribute to the defects in the developmental normal seen in Korean native cattle.

• 한국수산과학회지
• /
• 제25권5호
• /
• pp.331-340
• /
• 1992

본 연구는 우리나라 남해안에 분포하는 멸치 자원의 산란특성을 밝히기 위하여 1991년 3월부터 9월까지 멸치 성어의 생식소 조사로써 크기별 산란기, 산란빈도, 산란시각 및 산란수를 추정하였다. 산란기는 12cm 이상의 어체에서는 이른 봄철부터 초가을까지이며, 12cm 이하에서는 늦봄부터 초여름에 걸쳐서 2-3 개월간 산란에 참여하는 것으로 추정되었다. 성어의 산난빈도를 추정하고자 난경 빈도 분포를 구한 결과, 전체 난모세포군에서 분리되어 독립된 모우드를 형성하는 600um 이상인 수화란을 가진 개체의 비율은 성어의 약 $20\%$로서 5일에 1번 방란하는 것으로 추정되었다. 저녁에 채집된 어체의 난경 조성이 아침에 채집된 경우보다 전체적으로 큰 경향을 보였으며, 최대 난경군이 전체 난모 세포군에서 분리되어 있는 산난 직전의 현상을 보인 것으로 보아 야간에 산란이 일어난다고 볼 수 있었다. 포란수는 23,000-315,000립의 범위였으며, 최대 난경군의 난모세포수로부터 추정된 1회 산란수는 1,857-8,223립, 체중 1g당 산난수는 276-697입, 평균 산란수는 438입이었다.

• 한국발생생물학회지:발생과생식
• /
• 제21권4호
• /
• pp.407-415
• /
• 2017

In the present study, we investigated the role of binding immunoglobulin protein/glucose-regulated protein, 78-kDa (BIP/GRP78)-regulated endoplasmic reticulum (ER)-stress on meiotic maturation and cumulus cells expansion in porcine cumulus-oocyte complexes (COCs). Previously, it has been demonstrated that unfolded protein response (UPR)-related genes, such as molecules involved in ER-stress defense mechanisms, were expressed in matured oocytes and cumulus cells during in vitro maturation (IVM) of porcine oocytes. However, BIP/GRP78-mediated regulation of ER stress in porcine oocytes has not been reported. Firstly, we observed the effects of knockdown of BIP/GRP78 (an UPR initiation marker) using porcine-specific siRNAs (#909, #693, and #1570) on oocyte maturation. Among all siRNAs, siRNA #693 significantly reduced the protein levels of UPR marker proteins (BIP/GRP78, ATF4, and P90ATF6) in porcine COCs observed by Western blotting and immunofluorescence analysis. We also observed that the reduction of BIP/GRP78 levels by siRNA#693 significantly inhibited the meiotic maturation of oocytes (siRNA #693: $32.5{\pm}10.1%$ vs control: $77.8{\pm}5.3%$). In addition, we also checked the effect of ER-stress inhibitors, tauroursodeoxycholic acid (TUDCA, $200{\mu}M$) and melatonin ($0.1{\mu}M$), in BIP/GRP78-knockdown oocytes. TUDCA and melatonin treatment could restore the expression levels of ER-stress marker proteins (BIP/GRP78, $p-eIF2{\alpha}$, $eIF2{\alpha}$, ATF4, and P90ATF6) in siRNA #693-transfected matured COCs. In conclusion, these results demonstrated that BIP/GRP78-mediated regulation of UPR signaling and ER stress plays an important role in in vitro maturation of porcine oocytes.