• Asian-Australasian Journal of Animal Sciences
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• v.29 no.8
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• pp.1102-1110
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• 2016

The mammalian target of rapamycin (mTOR) regulates cellular processes such as cell growth, metabolism, transcription, translation, and autophagy. Rapamycin is a selective inhibitor of mTOR, and induces autophagy in various systems. Autophagy contributes to clearance and recycling of macromolecules and organelles in response to stress. We previously reported that vitrified-warmed mouse oocytes show acute increases in autophagy during warming, and suggested that it is a natural response to cold stress. In this follow-up study, we examined whether the modulation of autophagy influences survival, fertilization, and developmental rates of vitrified-warmed mouse oocytes. We used rapamycin to enhance autophagy in metaphase II (MII) oocytes before and after vitrification. The oocytes were then subjected to in vitro fertilization (IVF). The fertilization and developmental rates of vitrified-warmed oocytes after rapamycin treatment were significantly lower than those for control groups. Modulation of autophagy with rapamycin treatment shows that rapamycin-induced autophagy exerts a negative influence on fertilization and development of vitrified-warmed oocytes.

• Korean Journal of Animal Reproduction
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• v.12 no.2
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• pp.120-124
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• 1988

Rat oocyte-cumulus complexes were cultured in verious media in order to induce maturation division in vitro. When the complexes were cultured in mKRB containing estrous rat serum (ERS) and FCS of 5% instead of BSA higher proportions(83.3 and 86.7%) of oocytes matured to metaphase II in 20h compared to control(75%) and t도 maturation rates in mKRB plus FCS were generally higher than those in mKRB plus ERS. Fertilization and early cleavage rates in vitro of the intact oocytes matured in mKRB containing BSA and FCS were generally higher than those of cumulus-removed oocytes and these rates were higher in mKRB containing 5% FCS than those in mKRB containing BSA. These results indicate that maturation rate in vitro was greatly increased by the addition of FCS instead of BSA to mKRB solution and the presence of cumulus cells around oocytes prior to sperm insemintion may be responsible for the increase of in vitro fertilization and early cleavage rates.

• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.117-122
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• 1997

The aim of this study was to investigate the effect of the follicular culture from which the oocytes originate on their subsequent in vitro maturation ability. Ovarian follicles were isolated and cultured according to size(1~2mm, 2~6mm and 6~8mm) for 42~44 h. The rates of germinal vesicle breakdown(GVBD) in each groups were 87%(65/75), 82%(80/97) and 89%(47/53), but the oocytes maturation were su, pp.essed at anaphase-I stage. In spite of the adding porcine follicular fluid and/or hormones in maturation medium, maturation ability of oocytes from follicle cultured for 21~22 h were inhibited. When oocytes from follicle cultured for 4 h at various temperature were incubated for 38~40 h, the rates of oocytes maturation from follicle cultured at 2$0^{\circ}C$(51%, 26/51) and 39$^{\circ}C$(54%, 26/48) were significant higher(P<0.05) than group cultured at 4$^{\circ}C$(33%, 19/58). On the other hand, the GVBD were stared 2 h after culture of follicle of oocytes. To summairze, oocytes maturation by follicular culture were inhibited at anaphase-I stage in porcine. When the follicle cultured for 4 h, maturation were completed to metaphase-II stage. However, rates of GVBD in oocytes from follicular culture were higher than oocytes cultured in medium.

• Journal of Embryo Transfer
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• v.26 no.4
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• pp.251-256
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• 2011

Presently, the effect of 0.5 mM dibutyryl cAMP (dbcAMP)-supplemented maturation medium during different incubation time on meiotic arrest (germinal vesicle) and resumption (metaphase II) of porcine oocytes and embryonic development of porcine oocytes following in vitro fertilization (IVF) or parthenogenetic activation (PA) was determined. Porcine cumulus oocyte complexes (COCs) were cultured in 0.5 mM dbcAMP for 17, 22, 27, or 42 h, and an additional 22 h without 0.5 mM dbcAMP. The nuclear status was examined at each time point. Oocytes cultured from 39~49 h displayed more than 80% meiotic resumption. More than 85 % of meiotic arrest was presented at 17~22 h. Oocytes were cultured for 22 h with 0.5 mM dbcAMP and additional 22 h without dbcAMP to assess developmental potential following IVF or PA. There were no significant differences in blastocyst rates among the dbcAMPIVF, IVF, dbcAMP-PA, and PA groups, although cleavage rate of IVF group was significantly higher than those of dbcAMP-PA, and PA groups. In conclusion, 0.5 mM dbcAMP influenced meiotic maturation of porcine oocytes depending on incubation time of oocyte, although embryonic development was not improved in both IVF and PA.

• 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.

• 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.32 no.2
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• pp.71-79
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• 2008

Surface-enhanced laser desorption and ionization time-of-flight mass spectrometry (SELDI-TOF MS) is one of the recently developed proteomic technologies which is based on capturing proteins and peptides by chemically modified surfaces and highly sensitive for the analysis of complex biological samples. In the present study, to gain insights into oocyte maturation and early embryo development, SELDI-TOF-MS was used to find the protein candidates that are specifically or prominently expressed in porcine oocytes at the in vitro matured metaphase II (MIIl) and germinal vesicle (GV) stages. By selected CM10 chip, 16 candidates were found to be up-regulated in GV stage oocytes compared with in MII stage oocytes, their molecular weights were 8,180 (2 candidates), 10,226 (5 candidates), 15,767 (5 candidates) and 16,770 (4 candidates) Da respectively. And the expression of 29 candidates were higher in MII than in GV stage oocytes, their molecular weight were 10,832 (3 candidates), 17,743 (8 candidates), 20,122 (3 candidates), 22,131 (3 candidates), 24,857 (7 candidates) and 33,507 (5 candidates) Da, respectively. The expression of selected 13 candidates (0.2 and 1.0 % error tolerances) were analyzed using real time RT-PCR. The proteins that differentially regulated during oocyte in vitro maturation in the pigs may be potential biomarkers of oocyte maturation and quality.

• Korean Journal of Veterinary Service
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• v.21 no.3
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• pp.267-275
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• 1998

돼지 수정란의 체외생산은 난자의 체외성숙과 체외수정에 관한 기술의 부족으로 아직까지 만족스럽지 못한 수준이다. 특히 돼지 수정란의 체외생산에는 복잡한 세포질의 성숙과정과 높은 다정자침입율 및 전핵형성의 억제등의 문제점이 있다. 본 연구에서는 돼지 난자의 체외성숙 체계를 개선하기 위하여 transforming growth factor$\beta$(TGF$\beta$)의 첨가가 난자 및 난구세포에 미치는 효과에 대하여 검토하였다. 체외성숙용 배지에 TGF$\beta$를 1~10ng/$m\ell$의 농도로 첨가하여 미성숙 난자를 배양한 결과 성숙율이 높아졌다. TGF$\beta$의 효과는 난구세포가 제거된 난자의 성숙에도 효과적이었다. TGF$\beta$(를 첨가하지 않은 배양액 내에서는 배양 24시간 까지 metaphase-II로 성숙된 난자가 관찰되지 않았으나 TGF$\beta$를 첨가한 배양액 내에서는 관찰되었다. 한편, 난구세포가 부착된 난자의 성숙배양시 TGF$\beta$의 첨가시기에 따른 차이는 없었으나, 난구세포를 제거한 난자의 경우에는 성숙배양 전반기(59%) 또는 후반기(57%) 24시간 동안에만 TGF$\beta$를 첨가하는 것이 48시간 동안 계속하여 첨가(27%)하는 경우 또는 비첨가(38%)에 비하여 유의적으로 높은 성숙율을 나타냈다(p<0.05). 이와 같은 결과는 난구 세포가 돼지 난자의 체외성숙에 필수적이지만 TGF$\beta$는 난구세포가 제거된 난자의 체외성숙에 어 느정도 유익한 효과를 발휘하는 것으로 추측된다.

• Reproductive and Developmental Biology
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• v.32 no.1
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• pp.15-20
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• 2008

Pronuclear DNA microinjection has been the most universal method in transgenic animal production but its success rate of transgenesis in mammals are extremely low. To address this long-standing problem, we used retrovirus- and lentivirus-based vectors carrying the enhanced green fluorescent protein (EGFP) gene under the control of ubiquitously active cytomegalovirus (CMV) promoter to deliver transgenes to bovine embryos. The rate of transgenesis was evaluated by counting EGFP positive blastocysts after injection of concentrated virus stock into the perivitelline space of the bovine oocytes in metaphase II. Among two different types of lentivirus vectors derived from FIV (feline immunodeficiency virus) and HIV (human immunodeficiency virus), the former scored the higher gene transfer efficiency; almost 100% of the blastocysts developed from the oocytes infected with FIV-based vector were EGFP positive. As for the vectors derived Com HIV lentivirus, the transgenesis rate of the blastocysts was reduced to 39%.

• Korean Journal of Animal Reproduction
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• v.21 no.3
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• pp.211-217
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• 1997

This experiment was carried out to determine the possibility of using FDA on the selection of viable bovine immature oocytes. The results obtained in these experiments were summarized as follows; 1. The rates of nuclear maturation (metaphase II) of bovine oocytes according to FDA concentration were 92.5% (37/40) in the control and those rates in the dilution on FDA to 1:400,000, 1:800,000 and 1:1,600,000 were 74.4% (67/90), 80.3% (38/46) and 71.1% (32/45), respectively. 2. The fertilization rate ( 2-cell) in the control was 72.2% (39/54) and those rates in the dilution of FDA to 1:400,000, 1:800,000 and 1:1,600,000 were 28.8% (23/80), 66.7% (32/48) and 62.2% (28/45), respectively. In these results, a, pp.opriate concentration of FDA to bovine immature oocytes was 1:800,000. 3. Effect of FDA treatment to the blastocyst development of bovine oocytes was indicated that control was 22.2% (18/81) and FDA treatment groups which were classified to strong, partial and weak were 21.4% (36/168), 14.5% (9/62) and 0% (0/15), respectively. This result suggested that in vitro development to the blastocyst was severely reduced except strong group according to the FDA fluorescent level (P<0.05) and that using FDA is possible to select of bovine oocytes.