Transducin-like enhancer protein 1(TLE-1) is protein associated with cell proliferation. This study analyzed change of TLE-1 mRNA expression during in vivo and in vitro maturation in porcine oocytes. Oocytes and granulose cells were collected from follicles of <2 mm, 2～6 mm and >6 mm in diameter in slaughtered pig’s ovaries. Oocytes collected from follicles of 2～6 mm in diameter were used after in vitro maturation for 0, 10, 20 and 44 h. Cumulus cells and granulose cells were collected after treatment with hyaluronidase. In results, TLE-1 mRNA expression in oocytes collected from follicle >6 mm in diameter is increased, TLE-1 RNA expression in cumulus cells and granulosa cells from follicles <2 mm, 2 mm 6 mm and >6 mm in diameter. However, there is no significant difference. On the other hand, TLE-1 mRNA expression from oocytes cultured for 10 h and 44 h is increased, TLE-1 mRNA in cumulus cells cultured for 10 h is significant increased(p<0.05) than other culture periods. In conclusion, these results show that TLE-1 is expressed in all cell types of oocytes, cumulus cells and granulose cells, and associated with oocyte maturation.

The aim of this study was to investigate what protein(s) of porcine epididymal fluid (pEF) are able to enhance the nuclear maturation of porcine germinal vesicle (GV) oocytes in vitro. Proteins of pEF were fractionated by affinity, ion exchange, and gel filtration chromatography. Porcine cumulus-oocytes complexes (COC) from follicles were cultured in tissue culture medium (TCM 199) containing various fractions obtained by chromatography. Porcine COCs were also cultured in TCM 199 containing various meiosis inhibitors and pEF. After 24 or 48 h culture, oocytes were examined for evidence of GV breakdown, metaphase I, anaphase-telophase I, and metaphase II. When porcine COCs were cultured in the medium with meiosis inhibitor such as, dibutyryl cAMP (dbcAMP) and forskolin (Fo), more than 80% of oocytes were unable to resume meiosis. However, porcine COCs supplemented with pEF were able to overcome the inhibitory effect of dbcAMP and Fo. Maturation rate of oocytes was significantly (p<0.05) increased in the media supplemented with cationic protein(s) during in vitro maturation than in those with anionic protein(s) (44.1% vs 20.0%). When oocytes were cultured in the TCM 199 with fractions obtained by gel filtration, the maturation rate of oocytes was significantly (p<0.05) higher in fraction 11 containing 18 kDa than other fractions. The present study suggests that 1) dbcAMP and Fo prevent the spontaneous maturation of oocyte after isolation from follicles, and that pEF contain a substance(s) that improves meiosis resumption in vitro of porcine COCs, 2) cationic 18 kDa protein(s) are responsible for promotion of MⅡ stage.

In the present study, effects of concentration and time of culture in presence of roscovitine on nuclear maturation and meiotic spindle configuration, chromosomal alignment were examined in porcine oocytes. In experiment 1, porcine cumulus oocyte complexes (COCs) were cultured at in a 5% atmosphere in North Carolina State University 23 (NCSU-23) supplemented with 25, 50, 75 or roscovitine for 22 h and then were cultured for additional 22 h after removal of roscovitine. Nuclear maturation and morphology of the meiotic spindle and chromosomal alignment were examined to determine the optimal concentration of roscovitine in oocyte maturation. In experiment 2, COCs were cultured in NCSU-23 supplemented with roscovitine for 17, 20, 27 or 42 h and then an additional 22 h without roscovitine was followed to determine the optimal time of culture. The optimal concentration of roscovitine to arrest and resume meiosis of porcine oocyte was by examining nuclear status (p<0.05) and normal spindle and chromosome configuration. The optimal time of culture in presence of roscovitine to arrest meiosis of porcine oocyte was 17 h (p<0.05), although MII rates and normal morphology of the meiotic spindle and chromosomal alignment were not significantly different among various times of culture. In conclusion, the optimal concentration and time of culture in presence of roscovitine to arrest porcine oocytes are and 17 h, respectively.

Plasminogen activators (PAs) are serine proteases that convert plasminogen to plasmin. The PA/plasmin system has been associated with a number of physiological processes such as fibrinolysis, ovulation and fertilization. Although correlations have been reported between reactive oxygen species (ROS) and oocyte maturation, the relationship between PA activity and ROS is unknown. The present study was undertaken to determine the effects of cumulus cells on PA activity in matured porcine oocytes under xanthine (X)-xanthine oxidase (XO) system. When oocytes were matured under the X-XO system, the proportion of oocytes remaining GV stage was higher (p<0.05) in oocytes without cumulus cells. The incidence of degenerated oocytes was higher (p<0.05) in the X+XO ( and ) than in the control group ( and ). The proportion of TUNEL-positive oocytes and activity of caspase-3 were higher (p<0.05) in cumulus-free oocytes and oocytes exposed to ROS. Tissue-type plasminogen activator-plasminogen activator inhibitor (tPA-PAI) and tissue-type plasminogen activator (tPA) activity were detected in oocytes that were separated from cumulus-oocytes complexs (COCs) at 44 h of maturation culture, and only tPA was produced in oocytes that were denuded before the onset of maturation culture. On the other hand, the activities of PA were increased (p<0.05) when oocytes were cultured under the X-XO system. The higher activity of tPA was observed in denuded oocytes (DOs) underwent apoptotic changes by oxidative stress. In COCs, however, tPA-PAI as well as tPA activity was detected and apoptotic changes such as DNA cleavage or caspase-3 activation were not observed. These results suggest that tP A may be relevant to apoptotic cell death in porcine oocytes by oxidative stress.

Correlations between cumulus cells and germinal vesicle (GV) chromatin configuration were examined in porcine oocytes. Cumulus-oocyte complexes (COCs) were collected from 2～6 mm follicles and divided into three categories according to cumulus cell morphology. "A" group was compacted COCs with more than three cumulus cell layers. "B" group was COCs with less cumulus cell layers than "A" group. "C" group was COCs with one or less layer of cumulus cells. Cumulus cells were removed 0.1% hyaluronidase, and denuded oocytes were stained with Hoechst 33342. GV chromatin configuration was classified into GV-Con and GV-Dis. GV-Con meant that a nucleus was surrounded by condensed chromatin in a ring. GV-Dis meant that filamentous chromatin clumps were distributed in nucleus. The proportion (80.2%) of GV-Con in "A" group was significantly higher than "B" (62.0%) or "C" (44.9%). The proportion (55.1%) of GV-Dis in "C" group was significantly higher than "A" (19.8%) or "B" (38.0%). The meiotic competence of COCs was examined after 44 h culture. The proportion (90.0%) of oocytes reaching to metaphase II (M-II) in "A" group was significantly higher than "B" (76.5%) or "C" (45.5%). In conclusion, oocytes with good quality cumulus cell layers are synchronized early GV stage, and early GV stage is important for meiotic competence in pigs.

Matrix metalloproteinases (MMP) play important roles in extracellular matrix (ECM) remodeling during ovarian follicular development, oocytes development and ovulation. In an attempt to investigate the effect of MMP activation in development cumulus-oocytes complexes, we examined the localization and expression of MMP, and monitored MMP expression profile. Cumulus-oocytes complexes were collected and matured in vitro for 24 hr, 36 hr and 48 hr. A mRNA expression of MMP-2, MMP-9, TIMP-2 and TIMP-3 was detected in all culture medium regardless of CC, OC and COCs. Activity of MMP-2 in the OC progressively was increased from 24 hr to 48 hr. But MMP-9 was not detected in all culture medium. The localization of MMP-2 was also measured by immunohistochemistry analysis. The MMP-2 and TIMP-2 was detected in cumulus cell and oocyte zone pellucida. Expression of MMP-2 protein in the COCs was progressively increased from 24 hr to 48 hr. However, MMP-9 protein was progressively decreased from 24 hr to 48 hr. And TIMP-2 protein was most highly expressed in the COCs 36 hr. Expression of TIMP-3 protein in the COCs was progressively increased from 24 hr to 48 hr. In conclusion, these results suggest that MMP-2 plays a role in maintaining normal maturation and development by controlling the ECM inhibitor concentration on cumulus cell and oocytes.

The aim of this study is to investigate the effect of porcine epididymal fluid (pEF) on in vitro-maturation and subsequent fertilization of porcine follicular oocytes. Porcine cumulus-oocytes complexes retrieved from antral follicles were cultured in tissue culture medium (TCM)-199 supplemented with pEF of different concentrations. At 48 h after culture, development of oocytes to germinal vesicle (GV) breakdown, metaphase I, anaphase-telophase I, and metaphase II were examined. Significant (p<0.05) increase in the proportion of oocytes developed to MII stage was observed in oocytes cultured in pEF-containing TCM-199 than in oocytes cultured in pEF-free TCM-199 (46.2% vs 16.7%), which was a dose-dependent manner. Subsequently, the proportion of monospermic fertilization were significantly (p<0.05) increased in oocytes cultured in the TCM supplemented with pEF than those cultured in pEF-free TCM-199 (51.0% vs 24.1%). In the second series of experiment, the percentage of MII oocytes was significantly (p<0.05) increased after exposure of oocytes to pEF during the first 22 h period of culture than after exposure of oocytes to pEF during the next 24 h of culture, while no significant difference in the percentage of monospermy was observed. The results of this study demonstrate that pEF contains at least enhancing component(s) for nuclear maturation.

In the present study, effects of concentration of cryoprotectant solutions on the nuclear maturation of vitrifiedthawed porcine oocytes were examined. Oocytes were cultured in TCM-199 medium supplemented with 5% FBS at C in 5% and air. The percentage of monospermy in the toxicity group and vitrification group (22.0 3.0% and 31.5 3.5%) was decreased compared with that of the control group (44.0 4.0%). The percentage of in vitro development to blastocyst in the toxicity group and vitrification group (12.0 2.5% and 14.8 2.8%) was decreased compared with that of the control group (28.0 3.0%, p<0.05). The survival and in vitro developmental rate of oocytes vitrification-thawed with EDS and EDT + TCM-199 medium supplemented with 0.1% PVA were 46.3 3.0%, 54.5 3.8% and 14.8 2.5%, 16.4 2.7%, respectively. This results were lower than the control group (28.0 3.5%). The in vitro developmental rate of embryos vitrified with EDS and EDT supplemented PVA did not have a significant difference. The survival and in vitro developmental rate of vitrified-thawed morula and blastocyst embryos were 44.2 3.5%, 17.3 3.0% and 48.1 4.2%, 18.5 3.5%, respectively. Vitrified morulae and blastcyst embryos had a lower survival and developmental rates than their control counterparts.

This study was designed to investigate the effect of kinetin on in vitro development of parthenogenetic porcine oocytes exposed to demecolcine prior to activation. In vitro matured metaphase II stage oocytes were incubated in 0 or 2 g/ml demecolcine supplemented defined culture medium for 3 h and the oocytes were activated electrically. The parthenogenetic porcine embryos were then cultured in 0 or 200 M kinetin supplemented defined culture medium for 7 days. Regardless of demecolcine treatment, kinetin supplementation increased blastocyst rates significantly (7.0% versus 12.1% and 4.9% versus 8.5%; Control versus Kinetin and Demecolcine versus Kinetin + Demecolcine, respectively, p<0.05). Demecolcine treatment before activation tended to decrease blastocyst rates regardless of kinetin supplementation although it is not statistically significant. Total cell numbers in the blastocysts also tended to be elevated in embryos when supplemented with kinetin, however only the result between Kinetin and Demecolcine groups is statistically significant (37.6 7.2 versus 28.1 9.5, respectively, p<0.05). In conclusion, the present report shows that kinetin enhances developmental competence of parthenogenetic porcine embryo regardless of demecolcine pre-treatment before parthenogenetic activation when they were developed in defined culture condition.

The brilliant cresyl blue (BCB) has been used to select the developmental competent oocytes in pigs, goats and cows. Growing oocytes have a higher level of active glucose-6-phosphate dehydrogenase(G6PDH) compare to mature oocytes and are rarely stained compared to mature oocytes, because G6PDH converts BCB to colorless. First polar body extrusion regard as a guideline of meoisis completion. Selection of polar body extrude oocyte is more developmental competent to blastocyst than unselected. This study was conducted to compare the BCB test to the polar body extrusion on selection of developmental competent porcine oocytes for the production of blastocyst. Cumulus-Oocytes complex were exposed to 26uM BCB stain diluted in NCSU-23 for 90 min. There was no significant difference embryo development to blastocysts between BCB treated and not treated(19.58±1.99 vs 18.75±2.27 %), which means there was no detrimental effect of BCB exposure to oocytes. Normal fertilization is not differed among treatment groups from 70.0 to 78.4% development to blastocyst, beside polyspermy did not. To compare two different selection methods, BCB test and polar body extrusion, evaluate the developmental competent of IVP embryos. BCB+PB+(blue stained and polar body extruded, 20.71±0.45%) and BCB－PB+(colorless and polar body extruded, 20.04±1.29%) groups are significantly (p<0.05) higher developed than those of BCB+PB－(blue stained and no polar body, 13.24±0.73%) and BCB－PB－(colorless and no poladbody, 7.25±0.77%). These results showed that selection of polar body extruded oocytes method is more efficient than that of BCB test.

Interspecies somatic cell nuclear transfer (iSCNT) is a valuable tool for studying the interactions between an oocyte and somatic nucleus. The object of this study was to investigate the developmental competence of in vitro‐matured porcine oocytes after transfer of the somatic cell nuclei of 2 different species (goat and rabbit). Porcine cumulus oocytes were obtained from the follicles of ovaries and matured in TCM‐199. The reconstructed embryos were electrically fused with 2 DC pulses of 1.1 kV/cm for 30 μs in 0.3 M mannitol medium. The activated cloned embryos were cultured in porcine zygote medium‐3 (PZM‐3), mSOF or RDH medium for 7 days. The blastocyst formation rate of the embryos reconstructed from goat or rabbit fetal fibroblasts was significantly lower than that of the embryos reconstructed from porcine fetal fibroblast cells. However, a significantly higher number of embryos reconstructed from goat or rabbit fetal fibroblasts cultured in mSOF or RDH, respectively, developed to the morular stage than those cultured in PZM‐3. These results suggest that goat and bovine fetal fibroblasts were less efficacious than porcine‐porcine cloned embryos and that culture condition could be an important factor in iSCNT. The lower developmental potential of goat‐porcine and porcine‐bovine cloned embryos may be due to incompatibility between the porcine oocyte cytoplasm and goat and bovine somatic nuclei.