• Development and Reproduction
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• v.11 no.3
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• pp.263-272
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• 2007

Contrast to mouse where its in vitro maturation rates are high without specific supplements or presence of the cumulus cells, there are some species, such as porcine, where its in vitro oocyte maturation rates are still very low. This comparative study was conducted to investigate the role of malate dehydrogenase(Mor2) during oocyte maturation by RNAi in the mouse and porcine. The Mor2 double-stranded RNA(dsRNA) was prepared speciesspecifically and microinjected into the cytoplasm of denuded germinal vesicle(GV) oocytes. Oocytes were cultured for 48 h(porcine) and 16 h(mouse) in M199 with 10% porcine follicular fluid, pyruvate, p-FSH, EGF, cystein, and estradiol-$17{\beta}$. We measured changes in oocyte morphology, maturation rates and mRNA levels after Mor2 RNAi. We confirmed gene sequence-specific knock down of Mor2 mRNA in both species after Mor2 RNAi. In contrast to our previous finding that mMor2 RNAi resulted in GV arrest in the mouse, we found that pMor2 RNAi resulted in MI arrest in denuded porcine oocytes(58%), but developed to MII(84.4%) in COCs. To determine whether this difference between mouse and porcine RNAi is due to differences in culture media, we cultured mouse oocytes in the M199 media for 16 h after mMor2 RNAi. Mouse oocytes were developed to MII stage(62%) and there was no statistical difference compared to that of non-injected(76.8%) and buffer-injected(73.3%) control groups. Therefore, we concluded that the mouse and porcine oocytes are having different metabolic systems in relation to malate dehydrogenase for oocyte maturation. This could be a basis for differences in maturation rates in vitro in two species. Further scrutinized studies on the metabolic pathways would led us in finding better culture system to improve oocyte maturation rates in vitro, especially in more challenging species like the porcine.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.966-975
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• 1999

Technologies on preimplantation porcine embryos have been developed quickly and significantly. Successful development of systems for culture of porcine zygotes to the blastocyst stage has made it possible to utilize follicular oocytes for in vitro production of embryos and thus stimulated research on various embryo technologies. Recent technological development of embryo cryopreservation, separation of X- and Y-bearing spermatozoa and non-surgical embryo transfer has also made it easy to utilize in vivo- and in vitro-produced embryos for artificial manipulation to produce clones and transgenic pigs. Further progress in overcoming various problems associated with each embryo technology will result in acceptable efficiency to utilize porcine embryos with a high or increased quality. Combining these technologies will accelerate further expansion of the swine industry not only for meat production but also for the production of therapeutic recombinant proteins and xonografts.

• Reproductive and Developmental Biology
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• v.36 no.1
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• pp.71-77
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• 2012

The objective of this study was to examine the effect of thymidine treatment during $in$ $vitro$ maturation (IVM) of porcine follicular oocytes on blastocyst development. Porcine oocytes were treated with thymidine (10 mM, 20 mM and 30 mM) for 2 or 6 hr in the preiods of IVM I and/or II. The survival rates of the blastocysts in the 6 hr treatment groups of 10 mM and 20 mM during IVM I period were significantly higher than those of control group ($p$<0.05). However, the survival rate of the blastocysts in the 2 hr treatment group of 20 mM during IVM II period was significantly higher than control group ($p$<0.05). Furthermore, the survival rate of the blastocysts in the 6 hr treatment group of 30 mM during IVM II period was significantly lower than control group ($p$<0.05). Consistent with the previous result, blastocyst development of both IVM I and II treatment group was also showed as similar pattern. Total and apoptotic cell numbers of blastocysts derived from thymidine treated porcine oocytes were examined by using Tunel assay. The results showed that there was no significant differences in total cell number of blastocysts between thymidine treated and untreated groups. However, apoptosis-positive cells in the thymidine treated group (6 hr IVM I) were significantly lower than those of other groups ($p$<0.05). Taken together, these results indicate that high quality oocytes were selected by DNA synthesis mechanism according to high concentration thymidine treatment during porcine oocyte maturation. Therefore, we concluded that presumptive selected oocytes by thymidine treatment during maturation periods improved the further embryo development and embryonic quality of IVF embryos by decreasing the incidence of apoptosis in preimplantation porcine embryos.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.12
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• pp.1647-1651
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• 2004

The follicles (1.8 to 7.8 mm in diameter) were recovered from the ovaries in marketed pigs and the number of granulosa cells, the diameter of oocytes obtained from different development stages of the follicles and follicular fluid levels were determined. Correlations between size measurements and cell counts as well as the diameter of antral follicles and oocytes were also investigated. The results indicated that, while expanding in size, follicle numbers decreased with a greater atretic proportion. Granulosa cells increased in numbers continuously and remained unchanged beyond the size of 200 ${mm}^3$ in non-atretic follicles, whereas a sudden drop of granulosa counts was observed in atretic follicles. Follicular fluid, on the other hand, linearly increased its volume with follicle size and differed little between those of non-atretic and atretic follicles. Diameters of oocytes in non-atretic follicles increased to its maximum when follicles expanded to 150 ${mm}^3$ and maintained its size during later follicular expansion. It is concluded that, for in vitro culture, the optimal size of porcine follicle should be between 150 to 180 ${mm}^3$if they are collected from pre-pubertal gilts of marketing size slaughtered in an abattoir.

• Korean Journal of Animal Reproduction
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• v.24 no.2
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• pp.155-161
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• 2000

The morphological changes on nuclear phase of the germinal vesicle of porcine follicular oocytes during in vitro culture were examined. The high rates (75~77%) of the oocytes collected from follicles of 1~2mm or 6~100mm in diameter were at the GV-I to GV-II stages. When oocytes with or without cumulus cells after collection from follicles of 2~6mm in diameter were cultured for 5 h, the rates of oocytes at GV-IV to GV-Ⅵ stages were higher in oocytes with (52%) than in oocytes without (30%) cumulus cells. After 1 h of oocyte culture, there was no differences in the distribution of GV-IV to GV - Ⅵ stages in the media with or without catalase, xanthine and catalase＋xanthine. After 5 h of culture, however, the distribution of GV-IV to GV-Ⅵ stages were 46, 69, 69 and 70% for medium with none, catalase, xanthine and catalase＋xanthine. The highest rate of GVBD was also observed in the medium with catalase＋xanthine (6%). These results indicate that exposure of porcine follicular oocytes to catalase＋xanthine excels maturation to GV stage and enhances oocyte nuclear maturation.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.4
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• pp.501-508
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• 2013

The effects of amino acids and dipeptides on in vitro production of porcine embryos and accumulation of ammonia in culture medium during developmental stages were examined in this study. The maturation, fertilization and development of embryonic cultures were performed in modified Tissue culture medium (mTCM)-199 supplemented with 10% (v/v) porcine follicular fluid, modified Tyrode's albumin lactate pyruvate (mTALP) medium, and modified North Carolina State University (mNCSU)-23 medium, respectively. In addition, amino acids and dipeptides of different concentrations and combinations were used to treat the embryos. The addition of L-alanyl-L-glutamine (AlnGln)+L-glycyl-L-glutamine (GlyGln) significantly (p<0.05) improved oocyte maturation, fertilization and the incorporation and oxidation of 14C(U)-glucose when compared to the control group and other treatment groups. Additionally, 2-4 cell, 8-16 cell, morula and blastocyst development increased significantly (p<0.05) following treatment with AlnGln+GlyGln when compared to the control group and other treatment groups, while this treatment reduced the accumulation of ammonia. Taken together, these findings suggest that treatment with AlnGln+GlyGln may play an important role in increasing the rate of porcine oocyte maturation, fertilization and embryonic development by reducing the level of accumulated ammonia measured in the culture media.

• Clinical and Experimental Reproductive Medicine
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• v.12 no.1
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• pp.83-98
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• 1985

In order to study the mechanism of follicular atresia, the follicles of the porcine ovary were isolated according to the presence or absence of the corpus luteum and their size, and then classified to the normal? or atretic?follicle on the morphological observation such as the transparency, the vascularization of follicle, the nuclear phase of oocyte, and the homogeneity of the granulosa cell layer. The viability of granulosa cells was examined. The concentrations of progesterone ($P_4$), testosterone (T), and estradiol-17 beta ($E_2$) in each follicular fluid were estimated by the radioimmunoassay. The viability of granulosa cells in the atretic follicle was much lower than that of the normal one. The concentration of each steroid hormone increased as the follicular size was increased, was not different in quantity between the normal- and the atretic follicle of which diameter was below 3mm, and were much higher in the atretic follicle than those in the normal one of which diameter was above 7mm. The ratio of the concentration of E2 to T in the large atretic follicle valued higher than that in the normal one, but smaller in the small and medium atretic follicle than that in the normal one. The present study suggests that the mechanism of atresia of the large follicle may be different from that of the small and the medium follicle and that the amount of steroid hormones regarded as the one of the criteria for the atretic follicles.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.124-124
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• 2003

The successful development of embryos cloned by nuclear transfer (NT)have been dependent on a wide range of known factors including cell cycle of donor and recipient ooplast, oocyte quality, NT procedure and oocyte activation. The present study compared the development of cloned porcine embryos following different activation treatments. Cumulus-oocyte complexes (COCs) were aspirated from 26 mm follicles of slaughterhouse ovaries and cultured for 22 h in NCSU #23 medium supplemented with 10% porcine follicular fluid, 0.57 mM cysteine, 0.5 g/mL LH, 0.5 g/mL FSH and 10 ng/mL EGF. The COCs were further cultured for an additional 22 h in the same medium at $39{\cird}C$ in an atmosphere of 5% $CO_2$ in air, without hormonal supplements. Primary cultures of fibroblasts isolated from a female fetus on day 40 of gestation were established in DMEM + 15% FCS. For nuclear donation, cells at the 5th-6th passage were cultured in DMEM +0.5% FCS for 5 days in order to arrest the cells in G0/Gl. After enucleation, oocytes were reconstructed by transfer of donor cells and fusion with three DC pulses (1.4 KV/cm, 30 sec) in 0.28 M mannitol containing 0.01 mM $CaCl_2$ and 0.01 mM $MgCl_2$. Eggs were then divided into three treatment groups, control (without further treatment, Group 1), eggs cultured in 10 g/ml cycloheximide (CHX) for 5 h (Group 2), and eggs cultured in 1.9 mM 6-dimethylaminopurine (6-DMAP) for 5 h (Group 3). The eggs were then cultured in sets of 30 in 60 I drops of NCSU#23 supplemented with 4mg/ml BSA (essentially fatty acid free) until day 7 at $39{\circ}C$ in a humidified atmosphere of 5% $CO_2$. On day 4 the culture were fed by adding 20 I NCSU #23 supplemented with 10% FBS. Development rates into blastocysts were significantly higher (P<0.05) in Group 3 embryos compared to Group 1 controls ($27.6 \mu 2.7% vs. 20.1 \mu 4.1%$, respectively), but rates did not differ in Group 2 compared to control ($23.8 \mu 5.7%$). Total cell number in Group 3 blastocysts was however significantly higher (P<0.05) than in Groups 1 and 2 ($44.6 \mu 2.4 vs. 19.9 \mu 1.9 and 21.9 \mu 2.1$, respectively). These results suggest that 6-DMAP is more efficient than cycloheximide in the activation of electrically fused NT oocytes during in vitro production of cloned porcine embryos.

• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.240-240
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• 2004

The modification of in vitro maturation (IVM) conditions should be required to efficient production of matured porcine oocyte in vitro. Estradiol-17β (E₂) as steroid hormone exists in ovarian follicular fluid and plays a major role in ovulation. It has been reported that estradiol as well as other steroids are involved in keeping the oocytes in meiotic arrest. (omitted)

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2005.10a
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• pp.101-101
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• 2005