Ovarian Follicular Dynamics, Ovarian Follicular Growth, Oocyte Yield, In vitro Embryo Production and Repeated Oocyte Pick Up in Thai Native Heifers Undergoing Superstimulation

The objective of this study was to compare the effectiveness of the protocols for superstimulation of follicular growth in Thai native heifers. Heifers (n = 20) were randomly divided into four groups of five heifers/group. Heifers were given a single dose by i.m. administration of 100 mg Follicle Stimulating Hormone dissolved in polyvinylpyrrolidone (FSHp) at 24 h. Ovum pick up (OPU) occurred at 72 h (F24O72 protocol; Group 1) or 96 h (F24O96 protocol; Group 2), and at 36 h and OPU at 72 h (F36O72 protocol; Group 3) or 96 h (F36O96 protocol; Group 4) after follicular ablation. The dynamics of ovarian follicular growth were monitored by twice-daily ultrasonographic examinations. Blood sample collections were performed every 12 h after initiation of treatment for assessment of FSH, E2 and P4 profiles. All heifers were subjected to eight repeated sequential sessions of OPU. The follicular deviation commenced 24±5.32 h after follicular ablation in all groups. The circulatory FSH surged quickly from 24 to 36 h (>0.8 ng/ml) after follicular ablation and circulatory estrogen levels steadily increased from 36 h until OPU in all groups. At the end of the OPU sessions, the mean number of aspirated follicles/heifer/session in F36O72 protocol (Group 3) and F36O96 protocol (Group 4) were higher than in the two other groups (p<0.05). The number of cumulus-oocyte complexes (COCs), cleaved and day 8 blastocysts rates in the F36O72 protocol (Group 3) were higher than in the other groups (p<0.05). It can be concluded that a single dose i.m. administration of 100 mg FSHp at 36 h and OPU at 72 h after follicular ablation (F36O72 protocol; Group 3) was the most effective protocol for superstimulation of follicular growth for repeated OPU and subsequent in vitro embryo production in Thai native heifers.

Regulation of decidualization in human endometrial stromal cells through exchange protein directly activated by cyclic AMP (Epac)

INTRODUCTION

Human endometrial stromal cells (ESCs) undergo differentiation during the decidualization process. Decidualization is characterized by their enhanced production of IGF binding protein-1 (IGFBP-1), prolactin (PRL), and the forkhead transcriptional factor FOXO1, and transformation into more rounded cells, during the secretory phase of the menstrual cycle and subsequent pregnancy. Protein kinase A (PKA)-mediated cAMP signaling is crucial for this process. The present study was undertaken to examine the involvement of a mediator of cAMP signaling, exchange protein directly activated by cAMP (Epac), in decidualization of cultured ESCs.

RESULTS

Treatment of ESCs with the Epac-selective cAMP analog 8-CPT-2-OMe-cAMP (CPT) had no effect on IGFBP-1, PRL, and FOXO1 mRNA expression. However, CPT potentiated IGFBP-1 and PRL expression stimulated by the PKA-selective cAMP analog N(6)-Phe-cAMP (Phe) and activated Rap1, a downstream regulator of Epac signaling. Knock-down of Epac1, Epac2, or Rap1 significantly inhibited the Phe- or Phe/CPT-induced increase in IGFBP-1 and PRL expression, as well as Rap1 activation. Furthermore, CPT enhanced IGFBP-1 and PRL expression and the morphological differentiation induced by ovarian steroids, whereas Epac1, Epac2, or Rap1 knock-down suppressed these events.

CONCLUSION

These data provide evidence for the involvement of the Epac/Rap1 signaling pathway in cAMP-mediated decidualization of human ESCs.

47 DIFFERENCES IN MITOCHONDRIAL DNA COPY NUMBER AND EPIGENETIC PATTERNS OF MITOCHONDRIA-RELATED GENES IN CLONED COWS FROM THE SAME DONOR CELLS

The genetic codes of cloned animals and the donor are identical; however, incomplete reprogramming of donor nuclei during NT causes epigenetic abnormalities in cloned animals. Due to the genetic identity and epigenetic differences among clones, we can study epigenetic effects on the phenotypes by analyzing genetically identical clones. During the NT process, donor cell mitochondria (mt) are transferred into the recipient oocytes and mtDNA heteroplasmy is observed. Previous studies have reported various mtDNA transmission patterns not only in the cloned animal itself but also in the offspring of clones. However, differences in mtDNA copy number in cloned animals have not been reported, especially genetically identical ones. To analyze the genetic effects on mtDNA copy number in cattle, we compared actual mtDNA copy number per diploid genome in various tissues of clones derived from the same donor cells. From 5 genetically identical cloned cows (Japanese Black cattle, ages 68 to 82 months) and 6 non-cloned cows (Japanese Black cattle, ages 52 to 129 months), we isolated DNA from 8 kinds of tissues (heart, lung, liver, kidney, spleen, small intestine, muscle, and spinal cord) and measured mtDNA copy number by using real-time PCR. The absolute copy numbers of 2 mtDNA-encoded genes (COX1 and CytB) and 2 nuclear-encoded genes (H19 and IGF2) were measured and analyzed. To examine the epigenetic effects on mitochondria-related genes, we also analyzed DNA methylation patterns of mitochondria-related gene ANT4 (mitochondrial ADP-ATP translocase) in these tissues by the combined bisulfite restriction analysis (COBRA) method. The actual mtDNA copy number per diploid genome varied in tissues and individuals both in clones and non-clones (average in clones v. non-clones: heart: 11 839 ± 6210 v. 9569 ± 2555; lung: 2027 ± 1153 v. 1383 ± 173; liver: 5644 ± 2278 v. 4799 ± 1848; spleen: 1080 ± 844 v. 393 ± 265; kidney: 7034 ± 4448 v. 2939 ± 784; small intestine: 1330 ± 573 v. 437 ± 171; muscle: 9861 ± 3640 v. 7907 ± 3229; spinal cord: 3961 ± 1819 v. 2756 ± 496). The variability of mtDNA copy number in clones was significantly higher in the lung, spleen, kidney, small intestine, and spinal cord (P = 0.001, 0.026, 0.005, 0.021, and 0.014, respectively; F-test), but not in other tissues. Methylation of the ANT4 gene is quite tissue dependent: hypomethylated in the liver, muscle and spinal cord; moderately methylated in the heart, lung, and kidney; and highly methylated in the spleen and small intestine. The methylation patters of ANT4 were not different between clones and non-clones. These results suggest that mtDNA copy number is more influenced by nongenetic factors than genetic background.

299 A FEATURE OF SELF-RENEWAL PORCINE EMBRYONIC STEM CELL-LIKE CELL LINES ESTABLISHED BY INHIBITORS

Despite meticulous attempts for more than two decades, establishment of authentic porcine embryonic stem cell (ESC) from pig has never been successful. Although putative porcine ESC-like cells have been reported, such cell lines easily lose the ability of self-renewal, becoming extinct or differentiating after only a limited number of passages in culture. Porcine ESC-like cells exhibiting the property of self-renewal rather than pluripotency are considered a valuable resource in applications such as drug screening and toxicology testing in humans and livestock, and in veterinary medicine. In the present study, we evaluated the effect of glycogen synthase kinase 3β (GSK3β) inhibitor CHIR99021 and Erk signalling inhibitor PD184352 for use in establishing ESC-like cell lines derived from the inner cell mass (ICM) of porcine blastocysts produced in vitro. These ICM-derived cell lines were initially cultured and passaged in conventional human ES medium. They displayed so-called ESC-like morphology; for example, the isolated colonies began to grow as a monolayer with coarse cell–cell boundaries, in which the cells exhibited polygonal boundaries, high nuclear/cytoplasmic ratios, abundant lipid-like inclusions, alkaline phosphatase activity, and expression of markers of undifferentiated cells such as OCT4 and NANOG. After transfer to culture in ES medium containing the inhibitors, the morphology of the colony was dramatically changed, displaying a closely packed and smooth-edged colony with tight cell–cell boundaries. Remarkably, growth of the established cell lines is leukemia inhibitory factor (LIF)-dependent. The inclusion of inhibitors supports self-renewal, thus enabling continuous culture for over 100 passages while maintaining an undifferentiated state. High-passage-number cells continued to express undifferentiated marker genes and showed alkaline phosphatase activity and telomerase activity with an X chromosome status of XaXi. We further investigated the potential for differentiation of the established cell lines. The cells could easily form embryoid body-like spheres in suspension culture. When either the spheres or ESC-like cells were inoculated under the kidney or testis capsules of nude mice, classical teratoma formation was not observed after 2 to 3 months. However, histological analyses revealed apparent invasive proliferation derived from porcine cells. Although further analyses are required to characterise the property of the porcine ESC-like cells, we have recently succeeded in establishment of green fluorescent protein (GFP)-expressing stable cells lines, which will be useful for further investigation.

79 A COMBINATION OF ETHYLENE GLYCOL AND PROPYLENE GLYCOL IS SUPERIOR TO INDIVIDUAL CRYOPROTECTANTS FOR THE VITRIFICATION OF IMMATURE PORCINE OOCYTES

We compared the feasibility of ethylene glycol (EG) and propylene glycol (PG) for the vitrification of immature porcine cumulus–oocyte complexes (COC). Porcine COC collected from 3- to 6-mm follicles of slaughterhouse-derived ovaries were subjected to solid-surface vitrification (Somfai et al. 2010 Theriogenology 73, 147–156) either in 35% (v/v) EG or 35% (v/v) PG or in the mixture of 17.5% (v/v) EG and 17.5% (v/v) PG. After warming, the COC were subjected to in vitro maturation, IVF, and embryo culture according to Kikuchi et al. (2002 Biol. Reprod. 66, 1033–1041). Oocyte survival and maturation rates were assessed after in vitro maturation by evaluating membrane integrity and the extrusion of the first polar body. All live oocytes were subjected to IVF and in vitro culture. Cleavage and blastocyst rates were calculated from the total number of oocytes subjected to IVF on Day 2 (Day 0 = IVF) and Day 7, respectively. Total-cell (blastomeres) numbers in blastocysts were recorded on Day 7 after staining with Hoechst 33342. In Experiment 1, competence parameters of oocytes vitrified either in EG-based (EG group; n = 310) or a PG-based (PG group; n = 265) vitrification media were compared with those in the nonvitrified control (n = 160). The experiment was replicated 4 times. In Experiment 2, the competence parameters of oocytes vitrified with the combination of 17.5% EG and 17.5% PG (EG+PG group; n = 397) were compared with those in nonvitrified control (n = 245) and toxicity control (TC, exposed to cryoprotectants without cooling; n = 245) groups. Five replications were performed. Results were analyzed by ANOVA. Differences with P < 0.05 were considered significant. In Experiment 1, the mean survival rate of vitrified oocytes was significantly higher (P < 0.05) in 35% PG compared with that in 35% EG (73.3 and 25.9%, respectively). Maturation rates of surviving oocytes did not differ among vitrified (PG and EG) and nonvitrified control groups (71.1, 62.4, and 64.0%, respectively). After IVF of surviving oocytes, blastocyst formation rate in the group vitrified in EG was higher (P < 0.05) compared with that vitrified in PG but was lower (P < 0.05) compared with control (10.8, 2.0, and 25.0%, respectively). Mean cell numbers in blastocysts did not differ among EG, PG, and control groups (50.5, 47.7, and 48.7, respectively). In Experiment 2, survival of immature oocytes in the EG+PG group was 42.6%. After IVF, 10.7% of oocytes developed to the blastocyst stage in the EG+PG group, which was lower (P < 0.05) than those of the control (18.1%) and TC (23.3%) groups. Blastocyst rates in the control and TC groups were not statistically different. Mean cell numbers in blastocysts did not differ significantly among the EG+PG, control, and TC groups (61.6, 59.3, and 53.3, respectively). In conclusion, 35% PG provided a higher oocyte survival rate after vitrification compared with 35% EG. However, presumably due to toxic effects, 35% PG greatly reduced the development competence of oocytes. The combination of 17.5% EG and 17.5% PG yielded higher survival rates than did 35% EG, without any toxic effect on oocytes.

144 EFFECTS OF CO-CULTURE WITH FIBROBLASTS AND OVIDUCT CELLS ON IN VITRO PRODUCTION OF PORCINE EMBRYOS

Cell co-culture during in vitro maturation or embryo culture has been reported as a method to improve the efficiency of maturation or embryo development (Kidson et al. 2003 Theriogenology 59, 1889; Romar et al. 2005 Anim. Reprod. Sci. 85, 287). Here, we present the impact of different methods of co-culture with mouse embryonic fibroblasts or oviduct epithelial cells on in vitro embryo production in pigs. Cumulus–oocyte complexes (COC) were collected from follicles with diameter larger than 3 mm and used for in vitro embryo production based on the method of Kikuchi et al. 2002 (Biol. Reprod. 66, 1033) with minor modifications. There were 8 groups; group 1: maturation and embryo culture without cell co-culture (control group); group 2: maturation in the presence of fibroblasts; group 3: embryo culture in the presence of fibroblasts; group 4: both maturation and embryo culture in the presence of fibroblasts; group 5: maturation in the presence of oviduct cells; group 6: embryo culture in the presence of oviduct cells; group 7: both maturation and embryo culture in the presence of oviduct cells; group 8: both maturation and embryo culture in the presence of both fibroblast and oviduct cells. In vitro maturation (IVM) was carried out at 39oC under 5% CO2 in air for 44 h using NCSU-37 as basic medium. Matured oocytes were inseminated using epididymal frozen semen in IVF medium modified Pig-FM supplemented with 2 mM caffeine and 5 mg mL–1 bovine serum albumin (Kikuchi et al. 2002). The percentage of cleaved embryos and percentage of cleaved embryos which developed to the compact morula and early blastocyst stage were recorded. Results were analysed by one-way ANOVA followed by Dunnett’s test. To investigate the effects of co-culture with mouse embryonic fibroblasts and oviduct epithelial cells on oocyte maturation, some COCs cultured in groups 1, 2, 5, and 8 were fixed to assess their nuclear maturation to the metaphase II stage. The rate of matured oocytes in the groups 2, 5, and 8 was 76.85 ± 3.39% (n = 102), 79.11 ± 3.75% (n = 64), and 81.84 ± 3.93% (n = 66), respectively; these rates were increased significantly compared to the group 1 (55.87 ± 1.88%, n = 94; P < 0.05). The effect of co-culture on the fertilization and embryo development is shown in Table 1. Our results indicate that co-culture increases the rates of embryonic cleavage in all groups by comparison with the control group. However, a significant increase in the rate of morula-blastocyst was only observed when embryos were co-cultured with fibroblasts or when both maturation and culture were performed in co-culture with either fibroblasts or oviduct cells (groups 3, 4, 7, and 8). The most important increase in morula-blastocyst rate was recorded for the group of embryos co-cultured with fibroblasts (group 3). In conclusion, the co-culture with fibroblast or oviduct cells during maturation can improve oocyte maturation and cleavage rate, while co-culturing the embryos with fibroblasts seems sufficient to improve both the cleavage and the morula-blastocyst rates. Table 1.Effect of co-culture on the fertilization and embryo development in pig Supported by a grant from the NAFOSTED VN.

36 RESTORATION OF TELOMERE LENGTH IN CLONED PIG EMBRYOS DURING EARLY EMBRYOGENESIS IS NOT DEPENDENT ON TELOMERE LENGTH AND TYPE OF DONOR CELLS

Analyses on telomere length in cloned animals have revealed diverse results depending on the donor cell types. In mice and cattle, telomere length is reset during morula-blastocyst transition and the restoration is thought to be a telomerase-dependent process. However, it is still unknown whether the pattern of telomere elongation during this transition is dependent on donor cell types. In the present study, we examined the changes of telomere length during morula-blastocyst transition in cloned porcine embryos using different types of donor cell. Embryonic stem-like cells (ES), cumulus cells (C), fibroblasts at passages 7 and 10 (F7 and F10, respectively) were used as donor cells to produce NT embryos (ES, C, F7, and F10 groups, respectively). Telomere lengths of ES (35.8 ± 1.5 kb), C (24.4 ± 0.5 kb), P7 (18.7 ± 0.6 kb), and P10 (17.2 ± 0.1 kb) cells were significantly different. In contrast, cloned morulae in ES, C, F7, and F10 groups did not have any significant differences in telomere length (18.2 ± 0.3, 17.8 ± 0.7, 18.5 ± 0.3, and 18.4 ± 0.4 kb, respectively). Likewise, cloned blastocysts in ES, C, F7, and F10 groups had similar telomere length (22.3 ± 1.5, 23.5 ± 2.6, 20.2 ± 1.0, and 20.9 ± 1.0 kb, respectively). However, the telomere of the blastocyst was significantly longer (P < 0.05) compared with the morula in the respective group. Furthermore, relative telomerase activities of cloned morulae in ES, C, F7, and F10 groups (4.2 ± 0.4, 4.0 ± 0.5, 5.1 ± 0.4, and 4.9 ± 0.4, respectively) were significantly lower (P < 0.01) than those of cloned blastocysts in the same groups (8.2 ± 1.1, 8.6 ± 0.6, 12.5 ± 2.9, and 8.3 ± 1.1, respectively). The proportions of blastocysts in cloned embryos for ES, C, F7, and F10 groups (10.0 ± 5.2, 17.3 ± 2.9, 13.5 ± 2.9, and 13.1 ± 3.6%, respectively) did not significantly differ. Total cell numbers in blastocysts for ES, C, F7, and F10 groups (28.3 ± 2.9, 32.6 ± 3.6, 30.4 ± 3.1, and 27.4 ± 2.2, respectively) were not significantly different as well. In the present study, we found that the telomere elongation in cloned pig embryos occurs during morula-blastocyst transition. This is consistent with the previous findings in in vivo and in vitro fertilization and cloned embryos in cattle and mice. We also revealed that although different types of cells (ES, C, and F) or the same type of cells with different telomere length (F7 and F10) were used for NT, their resultant morulae and blastocysts had similar telomere length. This suggests that the telomere restoration during morula-blastocyst transition is independent of telomere length and type of donor cells. An increase in telomerase activity during morula-blastocyst transition indicates that the elongation of telomere length was likely a telomerase-dependent process. In conclusion, restoration of telomere length in cloned porcine embryos during morula-blastocyst transition was independent of telomere length and type of donor cells, and likely a telomerase-dependent process.

Studies of the humoral factors produced by layered chondrocyte sheets

The authors aimed to repair and regenerate articular cartilage with layered chondrocyte sheets, produced using temperature-responsive culture dishes. The purpose of this study was to investigate the humoral factors produced by layered chondrocyte sheets. Articular chondrocytes and synovial cells were harvested during total knee arthroplasty. After co-culture, the samples were divided into three groups: a monolayer, 7 day culture sheet group (group M); a triple-layered, 7 day culture sheet group (group L); and a monolayer culture group with a cell count identical to that of group L (group C). The secretion of collagen type 1 (COL1), collagen type 2 (COL2), matrix metalloproteinase-13 (MMP13), transforming growth factor-β (TGFβ), melanoma inhibitory activity (MIA) and prostaglandin E2 (PGE2) were measured by enzyme-linked immunosorbent assay (ELISA). Layered chondrocyte sheets produced the most humoral factors. PGE2 expression declined over time in group C but was significantly higher in groups M and L. TGFβ expression was low in group C but was significantly higher in groups M and L (p<0.05). Our results suggest that the humoral factors produced by layered chondrocyte sheets may contribute to cartilaginous tissue repair and regeneration.

The photonuclear neutron and gamma-ray backgrounds in the fast ignition experiment

In the fast-ignition scheme, very hard x-rays (hereinafter referred to as γ-rays) are generated by Bremsstrahlung radiation from fast electrons. Significant backgrounds were observed around the deuterium-deuterium fusion neutron signals in the experiment in 2010. In this paper the backgrounds were studied in detail, based on Monte Carlo simulations, and they were confirmed to be γ-rays from the target, scattered γ-rays from the experimental bay walls (γ'-rays), and neutrons generated by (γ, n) reactions in either the target vacuum chamber or the diagnostic instruments (γ-n neutrons).