• Clinical and Experimental Reproductive Medicine
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• v.25 no.1
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• pp.9-16
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• 1998

This study was performed to investigate the stimulating effect on oocyte maturation and cumulus cell expansion in TC199 media by human cord serum (HCS) supplementation. Immature mouse oocyte cumulus complexes (OCCs) were cultured in TC199 media supplemented with bovine serum albumin (BSA), HCS and human chorionic gonadotropin (hCG) instead of luteinizing hormone (LH) respectively, and the expression of cumulus expansion and oocyte maturation were observed. After 4hr and 24hr culture with or without OCCs, media containing 0.4% BSA, 10% HCS and 10 IV hCG respectively were collected and analyzed for changing concentrations of estradiol $(E_2)$, progesterone $(P_4)$, testosterone (T), and $PGF_{2\alpha}$. There were no elevation of $E_2$, T, and $PGF_{2\alpha}$ by OCCs culture, but minute elevation of $P_4$ level by 24hr OCCs culture in hCG supplementation (p=0.048). The stimulating pattern of cumulus expansion of OCCs by HCS and hCG supplementation was similar to our previously report using Ham's F-10 media, however oocyte maturation rates after 24hr OCCs culture in all media were increased by $20\sim30%$ compared to Ham's F-10 media. These results suggest that LH in HCS induce cumulus expansion probably by $P_4$ secretion of OCCs, and TC199 is efficient media for immature mouse oocyte maturation.

• Nutrition Research and Practice
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• v.16 no.3
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• pp.314-329
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• 2022

BACKGROUND/OBJECTIVES: Oocyte lipid droplets play a crucial role in meiosis and embryo development. Biotin is associated with fatty acid synthesis and is the coenzyme for acetyl-CoA carboxylase (ACC). The effects of a biotin deficiency on the oocyte lipid metabolism remain unknown. This study examined the effects of a biotin deficiency and its replenishment on murine 1) oocyte lipid droplet levels, 2) ovary lipid metabolism, and 3) oocyte meiosis. MATERIALS/METHODS: Mice were divided into 3 groups: control, biotin deficient (BD), and recovery groups. The control and BD groups were fed a control diet or BD diet (0.004 or 0 g biotin/kg), respectively. The recovery group mice were fed a BD diet until day 21, and were then fed the control diet from days 22 to 64. This study then quantified the oocyte lipid droplet levels, assessed the oocyte mitochondrial function, and examined the ability of oocytes to undergo meiosis. Ovarian phosphorylated ACC (p-ACC), lipogenesis, β-oxidation, and ATP production-related genes were evaluated. RESULTS: The BD group showed a decrease in lipid droplets and mitochondrial membrane potential and increased p-ACC levels. In the recovery group, the hepatic biotin concentration, ovarian p-ACC levels, and mitochondrial membrane potential were restored to the control group levels. On the other hand, the quantity of lipid droplets in the recovery group was not restored to the control levels. Furthermore, the percentage of oocytes with meiotic abnormalities was higher in the recovery group than in the control group. CONCLUSIONS: A biotin deficiency reduced the oocyte lipid droplet levels by downregulating lipogenesis. The decreased lipid droplets and increased oocyte meiosis failure were not fully restored, even though the biotin nutrition status and gene expression of lipid metabolism was resumed. These results suggest that a biotin deficiency remains robust and can be long-lasting. Biotin might play a crucial role in maintaining the oocyte quality.

• Journal of Genetic Medicine
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• v.18 no.1
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• pp.1-7
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• 2021

The oocyte quality is of great importance in infertility as it reflects the follicle developmental potential and further affects the embryo development, clinical pregnancy outcomes. The analysis of gene expression in somatic cells is an important study to better clinical in vitro fertilization (IVF) outcomes in embryo selection reflecting the appropriate communication between the oocyte and somatic cells. Specifically, somatic cell transcriptomic technology can help assess biomarkers of oocyte and embryo ability. The present article aims to overview the basic aspect of folliculogenesis and review studies involving changes in candidate gene expression of cumulus or granulosa cell related to clinical outcomes in human IVF.

• Molecular & Cellular Toxicology
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• v.4 no.3
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• pp.253-259
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• 2008

Human follicular fluid (HFF) is the in vivo microenvironment for oocyte maturation and includes a variety of proteins that could be involved in oocyte development and fertilization. We therefore used a proteomic approach to identify new HFF proteins. HFF from mature human follicles was obtained from five women following oocyte collection for in vitro fertilization (IVF). Ethanol-precipitated HFF run on two-dimensional gel electrophoresis (2DE) produced approximately 250 Coomassie brilliant blue-stained spots, 64 of which were identified using matrix-assisted laser desorption/ionization-mass spectrometry (MALDIMS). In this study, several proteins including complement factor H, inter-${\alpha}$ (globulin) inhibitor H4, inter-${\alpha}$-trypsin inhibitor heavy chain H4 precursor, human zinc-${\alpha}$-2-glycoprotein chain B, PRO2619, PRO02044, and complex-forming glycoprotein HC were new proteins that have not been previously reported in HFF using proteomic methods. Additionally, we identified alloalbumin venezia for the first time from trichloroacetic acid (TCA)-precipitated HFF. These HFF proteins could serve as new biomarkers for important human reproductive processes.

• Clinical and Experimental Reproductive Medicine
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• v.28 no.1
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• pp.65-72
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• 2001

Objectives: This study was to investigate the fertilization rate after intracytoplasmic sperm injection (ICSI) or partial zona dissection (PZD) of human and hamster sperm into hamster oocyte in in vitro fertilization (IVF). In addition, the possibility of clinical application was evaluated by the comparison of usefulness and difference of these method. Materials and Methods: Hamster immature oocytes were obtained from oviducts superovulated by PMSG and hCG, and hamster sperms were obtained from epididymis. The freezed human sperms were thawed before use. Fertilization were confirmed by two pronuclei, one pronucleus, swollen sperm head or/and two polar bodies at $7{\sim}8$ hour after ICSI or PZD. Results: The fertilization rates after ICSI and PZD of human sperm to hamster oocyte were 3.6%, 64.2%,73.6%, and 55.6% for negative control, positive control, ICSI, and PZD respectively, suggesting that ICSI only showed improved fertilization rate (p<0.01). The fertilization rates after ICSI and PZD of hamster sperm to hamster oocyte were 11.1%, 51.2%, 39.6%, and 72.7% for negative control, positive control, ICSI, and PZD respectively, suggesting that PZD only showed improved fertilization rate (p<0.01). PZD showed significantly higher fertilization rate than ICSI (p<0.05). Conclusions: As for the fertilization rate by ICSI and PZD using hamster oocyte in IVF, ICSI technique was considered to be more useful for human sperm and PZD technique for hamster sperm. Therefore, ICSI technique was considered more appropriate for experimental application using human sperm and hamster oocyte.

• Development and Reproduction
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• v.18 no.2
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• pp.117-125
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• 2014

Vitrification method is widely used in oocyte cryopreservation for IVF but the birth rates are lower than that of the fresh oocyte. One of the known main reasons is structural instability of meiotic spindle and chromosome systems of mature oocyte. To get the best way for keeping competence of matured oocytes, we studied the best conditions for vitrification focused on equilibration times. The mature oocytes were underwent vitrification with current popular method and analyzed the survival rates, microtubule stability and DNA integrity. The survival rates of recovered oocyte are almost same between groups and are more than 93%. The structural configuration of meiotic spindle was well kept in 10 min equilibration group and the stability rate was almost same with that of control. The chromosomal breakdown was observed in all experimental groups, but the chromosomal stability was higher in 10 min equilibration group than the other groups. The 10 min equilibration group showed best condition compared with the other groups. Based on these results, the equilibration time is one of the key factors in successful keeping for competence of mature oocyte. Although, more fine analysis about the effects of physical stress on oocyte during vitrification is needed to define the optimal condition, it is suggested that the optimal equilibration time to get competent oocyte in mouse is 10 min. Information acquired this study may provide insight into intracellular structural events occurring in human oocytes after vitrification and application for cryopreservation of human oocyte.

• Journal of Animal Science and Technology
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• v.63 no.2
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• pp.272-280
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• 2021

Cumulus-oocyte complexes (COCs), which contain immature oocytes, are matured in vitro for in vitro embryo production. Oocyte and cumulus cells are then separated using hyaluronidase. To date, there have only been a few reported cases of the toxic effects of hyaluronidase on porcine oocytes. The aim of this study was to compare the effects of bovine testis-derived hyaluronidase and recombinant human hyaluronidase on oocyte denudation and quality. Porcine COCs were matured for 44 h and denuded using different hyaluronidase concentrations and exposure times. Then, oocytes were activated by electrical parthenogenesis. In experiment 1, COCs were denuded using bovine-derived, ovine-derived (Hirax), and human recombinant (ALT-BC4) hyaluronidases for 10 and 20 min. In experiment 2, bovine-derived and human recombinant (ALT-BC4 and ICSI Cumulase®) hyaluronidases were used to denude the COCs for 2 and 20 min. In both experiments the oocytes were all completely denuded, and there was no degeneration. Rate of embryo development was significantly increased in group treated ALT-BC4 for 2 min and not significantly different in other treatment groups. In general it slightly decreased with longer exposure times. These results have confirmed that different sources of hyaluronidase do not have detrimental effects on the quality of porcine oocytes and suggest that the human recombinant hyaluronidase ALT-BC4 is suitable for oocyte denudation with an increased blastocyst rate.

• Clinical and Experimental Reproductive Medicine
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• v.38 no.4
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• pp.234-237
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• 2011

Objective: During stimulated IVF cycles, up to 15% of oocytes are recovered as immature. The purpose of this study was to investigate the trend of oocyte maturity in repeated ovarian stimulation for IVF. Methods: One hundred forty-eight patients were selected who underwent two consecutive IVF cycles using same stimulation protocol during 2008 to 2010. Ovarian stimulation was performed with FSH and human menopausal gonadotropin and flexible GnRH antagonist protocol in both cycles. Oocyte maturity was assessed according to presence of germinal vesicle (GV) and the first polar body. Immature oocyte was defined as GV stage or metaphase I oocyte (GV breakdown with no visible polar body) and cultured up to 48 hours. If matured, they were fertilized with ICSI. Results: Percentages of immature oocytes were 30.8% and 32.9% ($p$=0.466) and IVM rates of immature oocytes were 36.2% and 25.7% ($p$=0.077), respectively. A significant correlation was noted between percentage of immature oocytes in the two cycles (R=0.178, $p$=0.03). Women with >40% immaturity in both cycles (n=21) showed lower fertilization rate of $in$ $vivo$ matured oocytes (56.4% vs. 72.0%, $p$=0.005) and lower pregnancy rate (19.0% vs. 27.1%, $p$=0.454) after the second cycle when compared with women with <40% immaturity (n=70). In both groups, female age, number of total retrieved oocyte and embryos transferred were similar. Conclusion: In repeated ovarian stimulation cycles for IVF, the immature oocyte tended to be retrieved repetitively in consecutive IVF cycles.

• Development and Reproduction
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• v.5 no.2
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• pp.123-129
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• 2001

When mammalian oocytes undergo maturation, cumulus cells surrounding the oocyte exhibit remodeling of their structure known as cumulus expansion. Many molecules including hyaluronic acid participate in this remodeling. The present study aimed to investigate a possible existence of matrix metalloproteinases(MMPs) in the extracellular matrix(ECM) of human oocyte-cumulus complex. ECM was extracted from the human oocyte-cumulus complex. Gelatin gel zymogram of ECM exhibited 7 gelatinases having molecular weight of 300kDa, 240kDa, 200kDa, 180kDa, 116kDa, 97kDa, and 84kDa. This gelatinase profile was very different from that of ovarian mural granulosa cell extract or white blood cell extract, indicating that the oocyte-cumulus complex donating ECM was free from other than cumulus cells. When ethylenediaminetetraacetic acid or 1', 10'-phenanthroline was added to the reaction buffer during zymographic development, almost gelatinase activities were abolished, suggesting that they were MMPs. Following incubation of ECM in the presence of aminophenylmercuric acetate, an activator of proMMPs, 4 gelatinases of 240kDa, 180kDa, 97kDa, and 84kDa disappeared with the concomitant appearance of 80kDa, 65kDa, and 60kDa gelatinases. Based upon these observation, it is suggested that ECM of the human oocyte-cumulus complex consists of gelatinases, presumed to be MMP-2 and MMP-9 isoforms.

• Journal of Embryo Transfer
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• v.24 no.3
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• pp.145-150
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• 2009

This study was conducted to examine the effects of human follicular fluid and gonadotropin (FSH+HCG+rhEGF) on in vitro maturation, fertilization and development of human immature oocytes. Cumulus-oocyte complexes (COCs) were collected following for in vitro fertilization and embryo transfer (IVF-ET) cycles of the patients. At the time of oocytes collection, oocytes were classified into MII, MI and GV in accordance with their appearance (MII: Fully mature oocyte at metaphase II of meiosis; MI: Nearly mature oocytes at metaphase I of meiosis; GV: Immature oocytes at prophase I of meiosis). After controlled ovarian stimulation using gonadotropin(FSH) and human chorionic gonadotropin (HCG) in 70 ICSI cycles, 158 MI to MII matured oocytes were intracytoplasmic sperm injection (ICSI) ${\sim}4$ h after in vitro culture and 553 MII oocytes were ICSI after denudation. The aspirated MI and GV oocytes were cultured in culture medium containing 10% (v/v) serum protein substitute (SPS), 10% (v/v) human follicular fluid (hFF) and 10% (v/v) serum protein substitute (SPS)+1 IU/ml FSH+10 IU/ml HCG+10 ng/ml recombinant human epidermal growth factor (rhEGF). The maturation rate of immature oocytes was similar among the three group. When maturation medium was supplemented with 10% SPS, 10% hFF or gonadotropins, the fertilization rate of in vitro matured oocytes was higher in 10% SPS (80.0%), but there was no statistical significance (78.2%; hFF, 76.9%; gonadotropin, p>0.05). The development rate of human embryos developed to $6{\sim}8$ cells were not significant difference in the medium containing SPS, hFF and gonadotropins (65.6%, 65.9% and 66.7%). The results of these study suggest that human follicular fluid and gonadotropins supplemented in the culture medium was not effected on the in vitro maturation, fertilization and development of human immature oocytes.