• Journal of Embryo Transfer
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• v.13 no.2
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• pp.147-157
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• 1998

This study was conducted to investigate the effects of in vitro fertilization, culture and embryo development according to in vitro maturation rate, protectant composition and equilibrium time after frozen /thawing of bovine immature oocytes. This results obtained in studies on the effect of different cryoprotectants on the viability, maturation and development of in vitro bovine oocytes were as follow: 1.The post-thawing of immature oocytes matured to metaphase II during culture time for 0 to 26 h, and those group (62~3%) were low than control group (76.7%). The optimal maturation time of frozen-thawed immature oocytes was at 24 h. 2.The viability of cryopreserved immature oocytes was not affected by sort of cryoprotectants. The developmental competence of frozen4hawed oocytes was not affected by cryoprotectants. These results indicate that an optimal maturation time of frozen /thawed immature oocytes was at 24h. Furthermore the viability of cryopreserved immature oocytes was not affected by sort of cryoprotectants and developmental competence of frozen /thawed oocytes.

• Reproductive and Developmental Biology
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• v.30 no.2
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• pp.115-118
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• 2006

Cyclin B1 is known to reflect the M-phase promoting factor (MPF), a universal regulator of G2/M-phase transition, activity during the process of oocytes maturation. To investigate whether culture condition affects the maturation rate and the expression of cyclin B1 protein, bovine immature oocytes are stimulated and cultured according to the following protocols: Experiment 1: denuded oocytes (denude) only, COC only, denuded oocytes+granulosa cells (denude+GCs) and COC+GCs; Experiment 2: no-activation (control), 7% ethanol for 5 min and $10{\mu}l/ml$ ionomycin for 5 min at immediately before maturation. The maturation rates of denude and no-activation group were significantly lower in both experiments (P<0.05), respectively. Co-culture or stimulation method in bovine immature oocytes culture increases the cyclin B1 expression significantly in both experiments (P<0.05). Based on these results, culture condition affects the maturation rate and the expression of cyclin B1 protein during the first meiotic maturation in bovine immature oocytes.

• 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.

• Clinical and Experimental Reproductive Medicine
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• v.42 no.3
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• pp.118-125
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• 2015

Objective: The goal of this study was to evaluate the pregnancy potential of immature (metaphase I or germinal vesicle stage) oocytes retrieved in intracytoplasmic sperm injection (ICSI) cycles. Methods: A total of 1,871 couples with infertility underwent 2,984 ICSI cycles. Cycles in which three or fewer oocytes were retrieved were included in this study in order to evaluate the pregnancy potential of immature oocytes. Cycles were divided into five groups (group I-V), according to the maturation status of the oocytes at the time of cumulus cell removal and ICSI. The fertilization and pregnancy rates after ICSI were analyzed and compared among the study groups based on the maturation status of the retrieved oocytes. Results: The retrieval of only immature oocytes was associated with a significant decrease in the fertilization rate ($76.1%{\pm}37.3%$ vs. $49.0%{\pm}49.1%$, $66.7%{\pm}48.7%$; group I vs. group II, group III, respectively) and the average number of transferred embryos ($1.5{\pm}0.7$ vs. $1.1{\pm}0.4$, $1.1{\pm}0.6$). The cycle cancellation rate was significantly higher when only immature oocytes were retrieved. The clinical pregnancy rate decreased significantly when the transferred embryos had originated from immature oocytes (16.9% vs. 10.3%, 1.2%). Conclusion: In ICSI cycles, the fertilization potential and pregnancy potential of the immature oocytes retrieved in ICSI cycles were inferior to those of mature oocytes. Therefore, increasing the number of injectable oocytes and transferrable embryos by using immature oocytes after their spontaneous in vitro maturation does not necessarily improve pregnancy outcomes.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.2
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• pp.183-190
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• 1994

Purpose of the present study was to find the optimal culture conditions for the maturation and fertilization of immature oocytes by the use human body fluids and gonadotropins (Gn) in the mouse model. Cumulus-enclosed mouse immature oocytes were incubated in the medium containing various human body fluids with or without Gn in vitro, and examined to confirm nuclear maturation (NM) and fertilization. Female ICR mice were stimulated with 7.5 IU pregnant mares' serum gonadotropin (PMSG). Cumulus-enclosed immature oocytes were isolated at 48-52 hr post PMSG injection and cultured in TCM 199 supplemented with various concentrations (20, 50, and 70%) of human body fluids such as fetal cord serum (hCS), follicular fluid (hFF), peritoneal fluid (hPF) and amniotic fluid (hAF) in the presence or absence of 10 IU/ml PMSG and 10 IU/ml human chorionic gonadotropin (hCG) for 18 hr. Fetal calf serum (FCS) was used as a control for the supplements. Matured oocytes were fertilized with sperm collected from the epididymis of male mice. Fertilization was conducted in T6 medium containing 15 mgl ml bovine serum albumin, and confirmed at 6 hr post-insemination. Evaluation of nucler maturation and fertilization was carried out by rapid staining using fuchin. There was no significant difference between the effects of human body fluids and FCS supplements on nuclear maturation of cumulus enclosed mouse immature oocytes. When maturation medium was supplemented with 20% hPF or 20% hAF, fertilization rates were significantly (P<0.01) lower than that of 20% FCS, hCS and hFF groups. However, higher concentrations of body fluids during IVM were not more beneficial on fertilizability of oocytes. The addition of Gn significantly increased the fertilization rates in hPF and hAF groups (hPF without Gn; 51.5%, compared with 85.1% for addition of Gn, and hAF without Gn; 30.1% compared with 85.8% for addition of Gn) at 20% concentration. These results suggest that human body fluids at 20% concentration and gonadotropins can be used as supplements for the maturation of mouse immature oocytes in vitro. When gonadotropins supplemented with the human body fluids in the maturation medium, fertilizability of mouse immature oocytes was increased in hPF and hAF groups. These results can be applied to maturation of human immature oocytes in vitro.

• Korean Journal of Animal Reproduction
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• v.21 no.4
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• pp.355-362
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• 1997

This study was undertaken in an effort to product embryos through in vitro maturation(IVM), in vitro fertilization(IVF) and in vitro culture(IVC) after cryopreservation of immature and mature porcine oocytes. The experiments were conducted to investigate IVM rate of oocytes frozen with 3 different cryoprotectants and to examine IVF and IVC of frozen-thawed oocytes. The CEI(cumulus cells expansion index) after IVM of frozen-thawed immature oocytes was higher in oocytes frozen with PG＋PEG(propylene glycol plus polyethylene glycol) than those frozen with single cryoprotectant and this index was almost 90% of unfrozen oocyte's index(2.39 vs. 2.66). The IVF rate of all frozen oocytes was very low(68% of unfrozen oocytes) and the IVF rate of frozen immature oocytes was slightly higher than that of frozen mature oocytes(39.0% vs. 34.4%), but polyspermic penetration was higher in frozen immature oocytes(21.9% vs. 19.1%). The cleavage rate after IVF of frozen-thawed oocytes was 9.3% for frozen mature oocytes and 11.3% for frozen immature oocytes and this rate was significantly lower(P<0.05) than that of control(60.7%). The development to 8-cell stage was greatly lower in frozen mature oocytes than in frozen immature oocytes. The results indicate that the use of PG plus PEG as cryoprotectant may be very effective for vitrification of porcine oocytes and the frozen-thawed immature porcine oocytes can be used fro in vitro embryo production based on IVM, IVF and IVC system.

• Korean Journal of Animal Reproduction
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• v.22 no.2
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• pp.119-126
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• 1998

This study was conducted to find out the recovery rate of oocyte according to the different size of follicles from porcine ovaries, and the effect of in vitro maturation of porcine immature oocyte at the different transportation temperature of ovaries from slaughter house. The results obtained were summarized as follows : 1. The number of follicles per ovary was 22.5. The number of A-and B-typed oocytes(type A: cumulus-enclosed oocyte, type-B : corona-enclosed oocyte) per ovary was 2.4. The proportion of A-and B-typed oocytes was 29.6% of the total recovery oocytes. 2. When the immature oocytes were cultured for 36, 40, 44 and 48 h at 5$^{\circ}C$ transportation temperature of ovary, the germinal vesicle breakdown(GVBD) rates of porcine oocytes were 32.5, 28.2, 22.6 and 25.9% respectively. There were no significant differences between all the culture time for GVBD. Especially, most of oocytes were observed to arrest the development beyond germinal vesicle(GV) stage. 3. When the immature oocytes were cultured for 36, 40, 44 and 48 h at $25^{\circ}C$ transportation temperature of ovary, the GVBD rates were 81.0, 90.0, 91.7 and 92.9%, and the maturation (Met-II) rates were 51.2, 78.8, 76.2 and 78.6%, respectively. 4. When the immature oocytes were cultured for 36, 40, 44 and 48 h at 38$^{\circ}C$ transportation temperature of ovary, the GVBD rates were 93.9, 96.5, 96.5 and 95.3%, and the maturation rates were 62.2, 88.4, 84.7 and 86.0%, respectively. 5. The above results showed that the maturation rates of immature oocytes between $25^{\circ}C$ and 38$^{\circ}C$ transportation temperature of ovary did not differ significantly.

• Korean Journal of Animal Reproduction
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• v.20 no.1
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• pp.63-69
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• 1996

Bovine immature oocytes cultured for various times in TC-199 medium were inseminated with frozne-thawed spermatozoa in TC-199 medium supplemented with caffeine(5mM) and heparin(10$\mu\textrm{g}$/ml). Sperm penetraton was possible in oocytes at any stage of maturation, but penetration rates were lower in oocytes inseminated 0~16h (60~76%) than 20h (98%) after culture. Formation of male and female pronuclei were first observed in oocytes inseminated 8h after cultrue. Formation of male and female pronuclei were first observed in oocytes inseminated 8h after culture. The proportions of polyspermy were high(50~76%) in oocytes inseminated at any stage of maturation. Sperm penetration into oocytes at the GV stage started at 8h after insemination and the penetration rates gradually increased as time after insemination proceeds. The proportion(35%) of oocytes matured beyond metaphase-II 20h after sperm-oocytes incubation was low. When oocytes were incubated without spermatozoa in TC-199 medium, maturation rates were significantly higher (P<0.001) in those without(45 and 84% for 16 and 20 h) than with (0 and 36% for 16 and 20 h) caffeine and heparin. These results indicate that TC-199 medium with caffeine and heparin is not suitable for maturation and fertilization of immature oocytes and may inhibit male pronuclear formation in the cytoplasm.

• Reproductive and Developmental Biology
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• v.30 no.4
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• pp.301-305
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• 2006

The aim of this study was to investigate whether addition of porcine epididymal fluid (pEF) into culture medium during in vitro maturation influences the nuclear maturation of porcine germinal vesicle (GV) oocytes. Porcine cumulus-oocyte complexes (COCs) from follicles were cultured in tissue culture medium 199 (TCM 199) containing pEF. After 48hr of culture, oocytes were examined for evidence of GV breakdown, metaphase I, anaphase-telophase I, and metaphase II. The proportion of oocytes reaching at metaphase II (M II) stage was significantly (p<0.05) increased in oocytes cultured in the media supplemented with 10% pEF during in vitro maturation than in those without pEF regardless of cumulus presence or absence (54.6% vs 22.5%, 51.7% vs 24.2%). The supplementation of pEF during maturation of oocyte enhanced oocytes maturation in a dose-dependent manner in vitro. Also significant differences (p<0.05) in the percentage of MII oocytes were observed according to exposure period in pEF. Present study suggests that pEF contains a enhancing component(s) for nuclear maturation of porcine immature oocytes in vitro.

• Clinical and Experimental Reproductive Medicine
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• v.20 no.2
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• pp.157-160
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• 1993

The human follicular f1uids(F.F.) may be considered to contribute the maturation of the oocytes on the in vitro culture. To investigate the effects of epidermal growth factor (E.G.F.), which is present in mature and immature follicular fluids, we had experiments of mouse oocytes maturation in vitro. The endpoints assayed were rated as percentage of oocytes undergoing germinal vesicle breakdown(G.V.B.D.) and polar body(P.B.) formation at 12 hours after in vitro culture. The rates of G.B.B.D. were 87% in mature F.F. 68% in immature F.F. and 78% in Ham's F-10 medium respectively. And overall the mature F.F. seem to stimulate on in vitro oocyte maturation compared with either immature F.F. or Ham's F-10 medium. As the concentration of addition of E.G.F. in immature F.F., the rates of G.V.B.D. and P.B. formation were 82 %, 23% in addition with 2 ng/ml while 84%, 32% in addition with 4 ng/ml respectivly. And at the concentration of addition of E.G.F. in Ham's F-10 media as well, the rates of G.V.B.D. and P.B. formation were 84%, 40% and 82%, 44% in addition with each 2ng, 4ng. AccordinglY there was no influence on the oocytes maturation at the addition of E.G.F. to each immature F.F. and Ham's F-10 medium. In conclusion, the E.G.F. is not able to induce oocyte maturation independent of it's effects in immature F.F. and Ham's F-10 media.