• Journal of Embryo Transfer
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• v.14 no.2
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• pp.113-119
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• 1999

This study was performed to improve the development of the in vitro fertilized bovine embryos by the condition of in vitro maturation. COCs were matured in TCM 199 supplemented with 0.1% PVA, 10ng/ml EGF, Hormones (5$\mu\textrm{g}$/ml FSH, 10 IU hCG, 1 $\mu\textrm{g}$/ml estradiol 17-$\beta$) or granulsa cell+Hormones atmosphere 39$^{\circ}C$, 5% CO2, 95% air for 24hrs. Matured oocytes were fertilized with frozen-thawed semen capacitated with 5mM caffein in BO medium for 20 hrs. IVF embryos were cultured in TCM 199 containing with hormones(same as matured medium), 10% FBS and co-culture with bovine oviduct epitherial cells. Maturation rates of COCs were showed 73.8%, 78.5%, 83.2% and 87.6% respectively, and were significant differences between PVA, EGF, and Hormones, GC+Hormones(p<0.05). The cleavage rates of IVF embryos were revealed 72.5%, 78.4%, 82.3% and 84.2% and showed same tendency as maturation rates(p<0.05). The blastocysts matured by above maturation condition and cultured for 7~10 days after fertilization had 34.4, 43.6, 52.3 and 59.3 cells had no differences among the treatments. These results suggest that high molecules as a substitutes of serum and growth factor may induce nuclear resumption of COCs but we need more study to produce transferable IVF blastocysts by use of that agents.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.4
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• pp.500-506
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• 2009

A modified Tris-buffered medium (mTBM) has been widely used as an insemination medium for porcine in vitro fertilization (IVF). We examined whether mTBM could be used for bovine IVF. Bovine cumulus-oocyte complexes (COCs) were cultured in a serum-free medium containing 30 ng/ml EGF for 22 h. After culture, COCs were inseminated with spermatozoa for 12 h in mTBM containing 5 mM caffeine and 10 g/ml heparin. The penetration of oocytes increased significantly (p<0.05) as the sperm concentration increased from 0.1 (30%) to 1-10 $(87-100%){\times}10^6$ cells/ml. This was significantly different from values obtained at 1 (87%) and 10 $(100%){\times}10^6$ cells/ml. However, when COCs were inseminated with spermatozoa from different bulls, the proportions (62-100%) of oocytes penetrated varied according to the bull. The proportion (18%) of oocytes penetrated was significantly (p<0.05) lower in a fertilization medium without caffeine and heparin but increased with the addition of caffeine and/or heparin to the medium, and the proportion (93-96%) of oocytes penetrated increased significantly (p<0.05) when the medium was supplemented with heparin and caffeine. In this medium, sperm penetration was first observed at 3 h after insemination. Irrespective of the presence of glucose in the fertilization medium, the proportion (93-97%) of oocytes penetrated and the proportion (83-84%) of embryos at the ${\geq}2$-cell stage cultured in a chemically defined medium were not significantly different. However, the proportion of embryos developing to the blastocyst stage was significantly (p<0.05) higher in the presence (11%) of glucose in the fertilization medium than in its absence (2%). In conclusion, the present study demonstrated that bovine oocytes penetrated in vitro in mTBM can develop to the blastocyst stage and mTBM may be used for the in vitro production of bovine embryos.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.8
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• pp.1112-1121
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• 2019

Objective: Gram-negative bacteria lipopolysaccharide (LPS) has been reported to be associated with uterine impairment, embryonic resorption, ovarian dysfunction, and follicle retardation. Here, we aimed to investigate the toxic effects of LPS on the maturation ability and parthenogenetic developmental competence of bovine oocytes. Methods: First, we developed an in vitro model to study the response of bovine cumulusoocyte complexes (COCs) to LPS stress. After incubating germinal vesicle COCs in $10{\mu}g/mL$ of LPS, we analyzed the following three aspects: the expression levels of the LPS receptor toll-like receptor 4 (TLR4) in COCs, activities of intracellular signaling protein p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa B (NF-${\kappa}B$); and the concentrations of interleukin (IL)-$1{\beta}$, tumor necrosis factor (TNF)-${\alpha}$, and IL-6. Furthermore, we determined the effects of LPS on the maturation ability and parthenogenetic developmental competence of bovine oocytes. Results: The results revealed that LPS treatment significantly elevated TLR4 mRNA and protein expression levels in COCs. Exposure of COCs to LPS also resulted in a marked increase in activity of the intracellular signaling protein p-p38 MAPK and NF-${\kappa}B$. Furthermore, oocytes cultured in maturation medium containing LPS had significantly higher concentrations of the proinflammatory cytokines IL-$1{\beta}$, TNF-${\alpha}$, and IL-6. LPS exposure significantly decreased the first polar body extrusion rate. The cytoplasmic maturation, characterized by polar body extrusion and distribution of peripheral cortical granules, was significantly impaired in LPS-treated oocytes. Moreover, LPS exposure significantly increased intracellular reactive oxygen species levels and the relative mRNA abundance of the antioxidants thioredoxin (Trx), Trx2, and peroxiredoxin 1 in oocytes. Moreover, the early apoptotic rate and the release of cytochrome C were significantly increased in response to LPS. The cleavage, morula, and blastocyst formation rates were significantly lower in parthenogenetically activated oocytes exposed to LPS, while the incidence of apoptotic nuclei in blastocysts was significantly increased. Conclusion: Together, these results provide an underlying mechanism by which LPS impairs maturation potential in bovine oocytes.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.23-28
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• 2003

The present study was undertaken to investigate the effects of PVP concentration and exposure temperature to vitrification solution on the post-thaw survival, in vitro maturation and development of immature bovine oocytes (germinal vesicle stage). The vitrification solution (VS) consisted of 40% ethylene glycol (EG)+0.5 M sucrose (S)+10% FBS. PVP was added to VS: 0%, 5% or 10%. The cumulus-oocyte complexes (COCs) were diluted in VS as one step, after 2 min the COCs were loaded in straw and vitrified by direct immersion into liquid nitrogen. For thawing, the straws were plunged into $30^{\circ}C$ water bath for 10s. After thawing, the oocytes were diluted in 0.5 M (in DPBS with 10% FBS) sucrose solution for 5 min. The survival rate (FDA-test and trypan blue) of immature bovine oocytes was measured. The survival rate was higher in 5% PVP (91.5%) than in 0% (64.2%) or in 10% PVP (79.7%). The proportion of metaphase II formation was 69.35% in control (no vitrified COCs), 9.3% in 40% EG+0.5 M S+0% PVP and 21.05% in 40% EG+0.5 M S+5% PVP (p<0.05). The effect of room temperature ($25^{\circ}C$ for 10 min) and cold temperature ($4^{\circ}C$ for 10 min) on COCs were determined in this study. After IVF, the cleavage and blastocysts rate of oocytes exposed to room temperature and cold temperature in VS+5% PVP was significantly different (2 cell: 63.20% vs 37.97%, blastocysts: 18.40% vs 2.53%). The cleavage rates of frozen-thawed oocytes were 20.53% with PVP and 22.13% without PVP (p>0.05). Two out of 151 oocytes (1.32%) developed to blastocyst stage after frozen-thawed with 5% PVP (p>0.05). Development of oocytes after frozen-thawing to the 2 cell were not significantly affected with or without PVP following IVF. However, the vitrification of immature bovine oocytes with PVP maintained the ability to develop to the blastocyst stage after IVM-IVF and IVC, while no blastocysts were obtained from oocytes vitrified without PVP. These results suggested that PVP has a protective role for vitrification of immature bovine oocytes as far as survival is concerned, however, the protection was not sufficient enough to support blastocyst formation.

• Journal of Embryo Transfer
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• v.21 no.2
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• pp.157-162
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• 2006

It is well known that unidentified factors in sera, hormones and growth factors promote the proliferation of granulosa cells and nuclear maturation of bovine COCs (cumulus oocytes complexes) in vitro. Attempts had been developed the simple composition of culture media and similar system to in vivo conditions has been applied. In the present study, we investigated the effect of FGF (fibroblast growth factor) on in vitro maturation and in vitro development of Hanwoo COCs. When the COCs were matured in HPM 199 (Inst. of Functional peptide, Japan) containing 0.1, 1 and 10 ng/ml FGF for 24 hr, maturation rates to metaphase II ($70.0{\sim}75.0%$) were significantly higher (p<0.05) than that of control group (0 ng/ml FGF, 37.5%). When matured COCs with FGF were cultured in maturation medium after in vitro fertilization, developmental rates to blastocysts were 9.5, 0 and 2.9%, respectively, compared to 25.0% of the control group (p<0.05). When the matured COCs with FGF were cultured in HPM 199 (IFP971, Inst. of Functional peptide, Japan) containing 10% FBS, 0.8% BSA or 0.1% PVA (polyvinyl alcohol), the blastocyst formation rates were 12.4, 12.8 and 8.5%, respectively, while the rates of matured COCs with FGF and cultured with IVMD and IVD (Inst. of Functional peptide, Japan) without serum were 38.4% and 34.8%, respectively (p<0.05). These results suggested that FGF is available for in vitro maturation of bovine COCs and is not suitable for in vitro development, but further investigation would be need for finding the synergistic autocrine/paracrine fashion of other growth factors in early bovine embryo development.

• Development and Reproduction
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• v.8 no.2
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• pp.119-122
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• 2004

It is well known that unidentified factors in sera, hormones and growth factors promote the proliferation of granulosa cells and nuclear maturation of bovine COCs in vitro. Attemps had been developed the simple composition of culture media and similar system to in vivo conditions has been applied. In the present study, we investigated the effect of TGF-${\beta}$ on in vitro maturation and in vitro development of Hanwoo COCs. When the COCs were matured in TCM 199 containing 0.1, 1 or 10 ng/ml TGF-${\beta}$ for 24 hrs, metaphaseⅡ of COCs were obtained 95.8%, 100% of matured COCs, respectively and there were no differences among the concentrations of TGF-${\beta}$. Matured COCs with TGF-${\beta}$ cultured in maturation medium after in vitro fertilization, developmental rate to blastocyst were 0~0.8%. Matured COCs with TGF-${\beta}$ were cultured in TCM 199+10% FBS, 0.8% BSA, 0.1% PVA, blastocyst formation were showed in 12.4%, 12.8%, 8.5% of those and cultured in IVMD or IVD without serum were 38.4%, 34.8%, respectively. There were significant differences among the media (P<0.05). TGF-${\beta}$ is available for i vitro maturation of bovine COCs, but further investigation would be need for finding the synergistic autocrine/paracrine fashion of other growth factors in early bovine development.

• Journal of Embryo Transfer
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• v.29 no.3
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• pp.201-206
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• 2014

The objectives of the study were to determine an effective culture dish, culture duration and protein supplementation in medium for in vitro maturation (IVM) of oocytes of native zebu cows in Bangladesh. The ovaries of cows were collected from local slaughterhouse followed by aspiration of follicular fluid. The cumulus-oocyte-complexes (COCs) with more than 3 compact cumulus cell layers were cultured in tissue culture medium (TCM) 199 for maturation. The maturation of oocytes was determined by observing polar body under microscope. To determine an effective culture dish, 130 COCs derived from 48 ovaries in a well of 4-well dish and 102 COCs derived from 36 ovaries in drops covered with mineral oil within 35 mm petri dish were cultured for 24 hours. The rate of maturation of oocytes did not vary between 4-well dish ($51.3{\pm}15.0%$) and drops in petri dish ($52.4{\pm}11.6%$). To determine the effective culture duration, 185 COCs derived from 62 ovaries were cultured in drops for 18, 21, 24 and 27 hours. The rate of maturation of occytes ranged from $51.9{\pm}9.4%$ (18 hours) to $59.0{\pm}17.1%$ (27 hours) and the difference in maturation rate among different culture durations was not significant (P>0.05). To determine an effective protein supplementation, 63 oocytes from 19 ovaries were cultured separately in TCM 199 supplemented with either fetal bovine serum (FBS) or bovine serum albumin (BSA). The rate of maturation was significantly (P<0.01) higher in medium supplemented with FBS ($55.63{\pm}16.19%$) than that of BSA ($14.82{\pm}9.36%$). In conclusion, COCs of native zebu cows can be cultured for IVM either in 4-well culture dish or droplets in petri dish for 18 to 27 hours in medium supplemented with FBS.

• Journal of Embryo Transfer
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• v.15 no.3
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• pp.231-236
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• 2000

This study was conducted to examine the effects of exogenous gonadotropins (PMSG+hCG) and an antioxidant (cysteine) on in vitro maturation of bovine follicular oocytes. Cumulus-oocyte complexes (COCs) aspirated from 2 to 5 mm ovarian follicles were cultured for 22 to 24 hours in a modified bovine embryo culture medium (mBECM) supplemented with 3 mg/mL bovine serum albumin, to which PMSG (10 IU/mL) + hCG (10 IU/mL) and/or cysteine (0.6 mM) were added. When examined the expansion of cumulus ce1ls at the end of maturation culture, greater (p<0.05) expansion was found after addition of PMSG+hCG (79 to 96%) to mBECM than after no addition (0%), regardless of the presence or absence of cysteine in the medium. The addition of cysteine did not stimulate cumulus expansion, but a high proportion (92%) of expansion was achieved when COCs were cultured after the addition of PMSG+hCG and cysteine to the medium. No difference in the proportion of oocytes underwent germinal vesicle breakdown (initiation of maturation) was found after the addition of PMSG+hCG and/or cysteine to mBECM. However, nuclear maturation (development to the metaphase-II stage) of oocytes was significantly stimulated by the combined addition of PMSG+hCG and cysteine, compared with no addition. In conclusion, both exogenous gonadotropins and an antioxidant are important for nuclear maturation of bovine immature oocytes and these factors have a cell-specific stimulatory action.

• Journal of Embryo Transfer
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• v.20 no.3
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• pp.303-309
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• 2005

This study was conducted to examine the effects of OA on metaphase of meiosis II and the mitochondrial activity of cytoplasm in bovine cumulus oocytes complexes(COCs) during in vitro maturation. Hanwoo COCs were collected from the slaughterhouse cow ovaries and matured in TCM199 supplemented with $0.1\%$ PVA, 0.2 uM, 2 uM, 20 uM OA for the maturation rate of OA concentration. For the maturation effects between OA and cycloheximide(CX), COCs were matured in TCM199 with 25 ug/mL CX, 25 ug/mL CX (6 hrs culture) plus 2 uM OA or 2 uM OA only at a atmosphere $5\%\;CO_2,\;95\%$ air $39^{\circ}C$ for 6, 12, 24 hrs. To evaluate the nuclear types of matured COCs, cumulus cells were removedby $0.5\%$ hyaluronidase sol. and oocytes were fixed in 1:3 acetic acid ethyl alcohol for 30 sec. and then stained with $0.1\%$ basic Fuchsin sol. For the detection of fluoriscent intensity (FI) of matures oocytes, cumulus cells were removed same as performed above and were stained with 20 nM mite tracker for 20 min. at $39^{\circ}C$. Mitochondrial activity of FI in matured oocytes was imaged by laser conforcal microscopy (Fluoview, Olympus, Japan) and were measured scanned face on 5 um from median to endpoint of oocytes. Statical analysis of nuclear types observed the three replicates was carried out with ANOVA and Fisher's protected least significant difference test using the STATVIEW program. FI of matures oocytes was compared the multiples of the least intensity among the measured oocytes. Maturing in TCM199 supplemented with $0.1\%$ PVA, 0.2 uM, 2 uM, 20 uM OA, metaphase B were showed 72.0, 50.0, 70.0, $68.8\%$, respectively and there were different significant(p<0.05). In the case of treatment with OA and CX, metaphase were $73.8\%,\;8.2\%,\;45.5\%,\;73.7\%$ in $0.1\%$ PVA-TCM199, 25 ug/mL CX, 25 ug/mL CX plus OA or 2uM OA only, respeclively. FI was revealed the increasing tendency during the process of maturation. Whereas FI in CX was decreased about 3 times compared to the other treatments of 6 hrs maturation. We conclude that OA regulates bovine COCs maturation and induces the mitochondrial activity during the process of maturation.