mSOF Medium Research Articles

Evaluation of a serum-free culture medium for the enhanced vitrification cryosurvival of bovine in vitro-derived embryos

This is a feasibility study aimed to determine the effectiveness of a culture media designed to enhance embryonic cryopreservation based on laboratory-accessed quality phenotypes of in vitro produced bovine embryos. Recovered bovine oocytes were matured and fertilized in vitro and the presumptive zygotes that were obtained were randomly distributed into three culture media: (i) Control (C): modified synthetic oviduct fluid (mSOF) culture medium supplemented with 5 mg/mL BSA and 2.5% fetal calf serum; (ii) Medium A (MA): serum-free altered mSOF medium A; and iii) Medium B (MB): serum-free altered mSOF medium B. Embryos cultured in MA and MB presented a better viability after cryopreservation (P < 0.05) without affecting the production rates of blastocysts (P > 0.05, MB only) when compared to C. The MB-derived blastocysts had the highest (P < 0.05) hatching rate (26.1%, 53/203) and higher (P < 0.05) transferable embryos rate (92.1%, 187/203) compared to control-derived blastocysts (85.8%, 175/204). The total cell number in the embryos after vitrification/warming process was greater (P < 0.05) in the MA (144.9 ± 5.9) and MB (151.3 ± 7.1) compared to that in the control (121.4 ± 6.1). The number of large and giant cytoplasmic lipid droplets was reduced (P < 0.05) in MB-derived embryos compared to control-derived embryos. Additionally, the lipid profiles of MB-derived blastocysts were closely related to those observed in the in vivo-derived blastocysts. We observed different transcriptional profiles abundance of in vitro produced bovine embryos derived from control, MA and MB groups. Therefore, the novel MB culture medium increased embryonic cryosurvival and favored the production of bovine embryos in vitro with improved cellular and molecular laboratory-accessed quality phenotypes.

159 IN VITRO DEVELOPMENT OF CAPRINE EMBRYO USING CRYOPRESERVED BLACK BENGAL BUCK SEMEN

The purpose of this study was to check the competence of cryopreserved black Bengal buck semen to produce goat embryo through IVF. So far, cryopreserved black Bengal buck semen has not been used to produce goat embryos by IVF. For the study, fresh goat oviducts and ovaries were collected from slaughterhouse in a thermo flask containing 0.9% saline solution supplemented with antibiotic (400 IU mL−1 penicillin and 500 mg mL−1 streptomycin) at 30–35°C and transported to laboratory within 2–3 h of slaughter. Cumulus-oocyte complexes were collected from slaughterhouse ovaries, washed 5–6 times, and cultured in maturation media (TCM-199 + 10% FBS + 10 mg mL−1 FSH-P + 0.81 mM sodium pyruvate + 5% follicular fluid + 50 mg mL−1 gentamicin sulfate + 1 μg mL−1 oestradiol + 100 μM cysteamine) for 27 h in a 5% CO2 incubator at 38.5°C with maximum humidity. After 27 h of culture, cumulus cells were separated from matured oocytes by repeated pipetting using a fine pipette in fertilization Bracket and Oliphant’s (BO) medium. After removal of cumulus cells, the oocytes were transferred to acidified Tyrode’s medium for zona thinning for 52 s and were co-incubated with capacitated sperms for fertilization in fertilization BO medium at 38.5°C in 5% CO2 in air with maximum humidity. In the experiment I, freshly collected buck semen was used for IVF after processing for capacitation. In experiment II, cryopreserved buck semen straws were thawed and sperm were capacitated in vitro and used for fertilization. After 5 h of co-incubation, presumptive zygotes were washed thoroughly and cultured in embryo development medium for cleavage. Three different in vitro development media (RVCL, mSOF + 2.5% BSA, and KSOM + 0.5% BSA) were used. After 40 to 42 h, cleavage was observed and embryos were co-incubated with oviducal cells in replacement media for further development. In the fresh group, overall cleavage rates (%) were 37.76 ± 2.98, 39.60 ± 1.75, 29.01 ± 1.74 and morula formation rates (%) were 7.72 ± 3.38, 6.03 ± 1.29, 3.00 ± 3.00 in RVCL, mSOF, and KSOM media, respectively. However, in the cryopreserved group the overall cleavage rates (%) were 29.17 ± 2.56, 27.70 ± 2.31, and 24.17 ± 1.44 in RVCL, mSOF, and KSOM media, respectively, and morula formation (%) was achieved 2.93 ± 0.97 in RVCL media. These results indicate that cryopreserved black Bengal buck semen have competence to produce embryos and could be used for embryo development through IVF.

185 OVIDUCTAL CO-CULTURE CELL DID NOT REDUCE THE RATE OF CHROMOSOMAL ABNORMALITIES IN IN VITRO-PRODUCED BOVINE EMBRYOS

One of the major causes of embryo failure on in vitro-produced cattle embryos is their increased rate of chromosomal abnormalities. It was demonstrated that they can be increased by the pre- and post-environmental conditions of culture, such as the culture media and supplementation and culture atmosphere among others. Furthermore, it was suggested that the percentage of chromosomal abnormalities detected could be used as an indirect methodology to evaluate the embryo stress during culture. The use of oviduct cells in co-culture was employed as a technique that improves the embryo quality in different culture systems in cattle, probably by modulating the variations in the embryo environment or detoxifying the culture media. For that reason, we aimed to determine if the use of an oviducal co-culture system could reduce the percentage of chromosomal abnormalities in in vitro-produced cattle embryos. Oviducal cells were obtained from abattoir oviducts, and plated and cultured in TCM-199 media following standard procedures. Cumulus-oocyte complexes were also obtained from the abattoir and matured in a standard media (TCM199, with glutamine, pyruvate, FSH, LH, and antibiotics) for 20 h (38.5°C, 5% CO2). Matured oocytes were fertilized in IVF-TALP with 1 × 106 spermatozoa/mL (previously selected through a 45–90% Percoll™ gradient) for 18 h using the same conditions. Presumptive zygotes (n = 653) were divided into 2 groups and cultured in the mSof medium for 72 h, with (SOV) or without (SOF) the addition of oviducal cells. In total, 108 embryos were successfully karyotyped following our standard laboratory techniques. Chromosomal numerical abnormalities were evaluated by direct observation at 1250× magnification in a bright-field microscope using a simple Giemsa staining. The percentage of diploid embryos (54/58 in SOV and 47/53 in SOF) and abnormal embryos (4/58 in SOV and 6/53 in SOF) were nonsignificant (P &gt; 0.05; Z-score test for 2 population proportions). Our results suggest that the use of oviducal cells as a co-culture supplementation in in vitro-produced cattle embryos do not improve the percentage of chromosomal abnormalities detected.

Cysteamine and b-mercaptoethanol supplementation improves the in vitro embryo development in buffaloes (Bubalus bubalis)

The objective of the present experiment was to investigate the effect of cysteamine and b-mercaptoethanol supplementation on in -vitro maturation, cleavage of oocytes and development of embryo in buffalo (Bubalus bubalis). Oocytes were aspirated from abattoir ovarian follicles of 3-10 mm diameter followed by maturation in the media in vitro containing cysteamine/b-mercaptoethanol (treatment) and without antioxidant (control). Matured oocytes were co-incubated with sperm (approx.1×106/ml) of Murrah bull in mSOF medium using heparin (10 μg/ml). After 22 h of oocyte-sperm incubation, fertilized oocytes were stripped of cumulus cells and cultured in mSOF medium for 8 days to study embryo development. The oocyte maturation rate improved significantly (P&lt;0.05) following addition of 50 or 100 μM of cysteamine and 10, 50 and 100 μM of b- mercaptoethanol (ME), respectively as compared to control. The cleavage rate was found to be significantly (P&lt;0.05) higher at 50 and 100 μM of cysteamine and at all concentrations of b-mercaptoethanol as compared to control and development of embryos to morula stage was significantly (P&lt;0.05) improved with 50 μM cysteamine/ b-mercaptoethanol.

Somatic Cloning in Cats Using MI or MII Oocytes

Animal production via SCNT provides a unique tool for protection of valuable individuals, conservation of vulnerable and endangered species and production of transgenic animals. A total of 167 MI and 219 MII stage oocytes were used as the material of the study. The oocytes were enucleated at 44 h after in vitro maturation by aspiration of the polar body and the MI or MII plates. Cycling granulosa cells were used for nuclear transfer. Cell fusion was induced with DC pulses of 2.0 kV/cm 60µs, 0.1s apart (2x) delivered by a BTX Electrocell Manipulator 200 (BTX, San Diego, CA, USA). After fusion, the embryos were activated by 1.0 kV/cm 20µs DC pulses 0.1s apart (2x) followed by 2 mM 6-DMAP (6-dimethylaminopurine) incubation in culture medium for 4 h in a humidified atmosphere of 5% CO2, 5% O2, and 90% N2 at 38°C. The somatic cell transferred embryos were cultured for 8 days in mSOF medium supplemented with 0.4% BSA in a humidified 5% CO2, 5% O2, and 90% N2 atmosphere at 38°C. After in vitro culture period, all embryos transferred to HSOF containing Hoechst 33342 (5 μg/mL) and the cell numbers were counted under ultraviolet light using a fluorescent microscope. The fusion (66.66 vs 21.55%) and cleavage rates (15.75 vs 11.11%) were significantly higher in MII stage oocytes than MI stage oocytes (P<0.02). While SCNT embryos were developed to morula stage in MII group (14; 9.58%), all the cleaved embryos were arrested at the 2-4 cell stage in MI group. None of the embryos was developed to blastocyst stage in both groups.

40 TRICHOSTATIN A TREATMENT EFFECTS ON IN VITRO DEVELOPMENT OF INTERSPECIES NUCLEAR TRANSFER CAT EMBRYOS DEPEND ON RECIPIENT CYTOPLASM SPECIES

The developmental ability of interspecies somatic cell nuclear transfer (iSCNT) embryos decreases as the taxonomic distance between the donor and recipient species increases. Treatment of cat iSCNT embryos using bovine oocytes with 50 nM of trichostatin A (TSA) improves in vitro embryonic development (Wittayarat et al. 2013 Cell. Reprogram. 15, 301–308). This study investigated whether the TSA treatment effects differ between the development of cat iSCNT embryos reconstructed with porcine and bovine oocytes. Porcine and bovine cumulus-oocyte complexes were in vitro matured for 44 h and 24 h, respectively. After cumulus cell removal, enucleation was performed by aspiration of the metaphase II plate and the first polar body using a piezo-driven pipette. A cat fibroblast cell was then injected into cytoplasm of successfully enucleated oocyte. Reconstructed cybrids were electrically activated by a single 1.5 kV cm–1 pulse for 100 µs (pig-cat embryos), or a 2.3 kV cm–1 pulse for 30 µs (cow-cat embryos). Pig-cat and cow-cat embryos were cultured in porcine zygote medium (PZM)-5 and modified synthetic oviducal fluid medium (mSOF), respectively. After electrical activation, pig-cat and cow-cat embryos were cultured in medium supplemented with 5 µg mL–1 cytochalasin B + 50 nM TSA (TSA group) or without TSA (control group), and the cow-cat embryo medium was also supplemented with 10 µg mL–1 cycloheximide. After 2 h, TSA-treated pig-cat and cow-cat embryos were incubated in medium supplemented with TSA for 22 h, followed by 48 h incubation without TSA. Pig-cat and cow-cat control embryos were cultured in medium without TSA for 70 h after activation. Then, all pig-cat and cow-cat embryos were cultured in porcine blastocyst medium (PBM) or mSOF medium supplemented with 5% fetal bovine serum, respectively, for 5 additional days. Four to seven replicates were performed for each experiment. Data were analysed using Student's t-test. For pig-cat embryos, no difference was observed in cleavage rates between both groups, but development to the blastocyst stage was higher in the pig control group (n = 147, 8.0%) than that of pig TSA group (n = 131, 0.7%; P &lt; 0.05). In contrast, development to the blastocyst stage in cow-cat embryos was not observed in the cow control group (n = 125, 0%), but it was observed in cow TSA group (n = 136, 3.7%). These results indicate that TSA treatment effects are species-specific, but those effects remain to be clarified.

Effect of Different Activation Techniques on Immature and In Vitro Matured Cat Oocytes

This study was conducted to determine the most successful techniques on inmature and in vitro-matured cat oocytes that were parhtenogenically activated using 6-dimethylaminopurine (6-DMAP) and cycloheximide (CHX), in combination with electrical stimulation and calcium ionophore. After 44 h of in vitro maturation, the oocytes with a polar body were separated as mature (M II) and those without a polar body were considered as immature. Four different activation treatments and two control groups were used for parthenogenetic activation with both mature and immature cat oocytes. After 48 h of activation, the oocytes were examined and the non-cleaved oocytes removed. The cleaved oocytes/embryos were cultured in vitro in mSOF medium for an additional four days. After six days of in vitro culture (IVC), embryo quality was evaluated. The results in the present study suggested that (I) both in vitro matured and immature cat oocytes have a potential to develop to morula and blastocyst stages after parthenogenetic activation, (II) electrical stimulation + 6-DMAP is a more useful technique for both matured and immature cat oocytes and (III) to our knowledge, this is the first report that describes morula and blastocyst formation from parthenogenetically activated immature cat oocytes.

33 PROPAGATION OF ELITE LIFESAVER DOGS BY SOMATIC CELL NUCLEAR TRANSFER

Canine somatic cell nuclear transfer (cSCNT) has been used as a useful tool for propagation of elite working dogs. In 2009, 7 cloned dogs were successfully produced using somatic cells derived from the excellent drug-sniffing dog of Korea Customs Service. All cloned dogs perfectly performed drug detection in Incheon International Airport. The objective of the present study was to compare the efficiency of the 2 activation culture media to clone the retired Baekdu, a veteran rescue dog that performed lifesaving activities worldwide for 6 years in Korea National Emergency Management Agency (NEMA). Ear tissue was collected from a 10-year-old male German Shepherd and fibroblasts were cultured for cSCNT. The cells were injected into the perivitelline space of enucleated in vivo-matured dog oocytes, fused with electric stimulation using an electro cell fusion apparatus (Nepa Gene Co. Ltd.), and activated chemically. In the activation protocol, 2 different types of media were tested to investigate the effect of proteins with undefined functions. The first medium was a modified synthetic oviduct fluid (mSOF), which is a complex culture medium with BSA that includes undefined functions. The second medium was the porcine zygote medium (PZM-5), which is a chemically defined medium with polyvinyl alcohol (PVA). The fused couplets were activated by mSOF medium supplemented with 1.9 nM DMAP (SOF-DMAP), and PZM-5 supplemented with 1.9 nM DMAP (PZM-DMAP) for 4 h, followed by 4 min of calcium ionophore treatment. Then, reconstructed oocytes were transferred into the uterine tube of naturally estrus-synchronized surrogate dogs. In the PZM-DMAP group, a total of 56 activated cloned embryos were transferred into 3 female recipient dogs, and a total of 64 activated cloned embryos from the SOF-DMAP group were transferred into 4 female recipients. Pregnancy diagnosis was performed using a SONOACE 9900 (Medison, Seoul, Korea) ultrasound scanner with 7.0-MHz linear-array probe between 30 and 35 days after embryo transfer. As a result, pregnancy was detected in 1 out of 3 surrogate mothers that received cloned embryos from the PZM-DMAP group (33.3%), and 1 pregnancy (25%) was detected in 4 surrogate mothers receiving cloned embryos from the SOF-DMAP group. Two pregnant dogs each gave birth to 1 healthy cloned puppy by cesarean section. This study shows that existence of proteins with undefined functions in activation medium did not affect the dog cloning. In addition, the number of elite working dogs in diverse fields can be increased by the NT technique using donor cells derived from small tissue of elite working dogs. This study was supported by RDA (no. PJ0089752012), RNL Bio (no. 550-20120006), IPET (no. 311062-04-1-SB010), Research Institute for Veterinary Science, and TS Corporation.

Effect of mSOF and G1.1/G2.2 Media on the Developmental Competence of SCNT‐Derived Bovine Embryos

The objective of this study was to compare the effect of two culture media: modified synthetic oviductal fluid (mSOF) and G1.2/G2.2, on the developmental competence of bovine somatic cell-cloned embryos. Cloned embryos were produced by transferring adult skin fibroblasts into enucleated MII oocytes. After activation, the reconstructed embryos were randomly allotted to either mSOF or G1.2/G2.2 for culture (the embryos were transferred from G1.2 to G2.2 on days 3 of culture). The development competence of cloned embryos in these two culture systems was compared in terms of cleavage rate, blastocyst formation rate and apoptosis cell number in day 7 blastocyts. To investigate the in vivo developmental competence of cloned embryos in the two culture systems, a total of 87 and 104 blastocysts derived from mSOF and G1.2/G2.2 medium groups were transferred individually to recipient Angus cows, respectively. No differences were observed in terms of cleavage rate, day 7 blastocyst rate and blastocyst cell number between these two culture systems. However, the day 6 blastocyst formation rate was significantly higher in G1.2/G2.2 than that in mSOF. In addition, blastocysts cultured in mSOF have a higher percentage of apoptotic blastomeres compared to those in G1.2/G2.2 (8.5 ± 1.2 vs 16.8 ± 1.5, p<0.05). Although difference in pregnancy rate was not observed 40 days after embryo transfer, significantly higher pregnancy rate was observed in G1.2/G2.2 group after 90 days of embryo transfer (12.4% vs 37.5%, p<0.05). Moreover, calving rate was significantly improved in G1.2/G2.2 group compared to mSOF group (27.9% vs 6.7%, p<0.05). In conclusion, our results indicate that G1.2/G2.2 can improve developmental competence of bovine SCNT embryos both in vitro and in vivo, which is more suitable for culture of bovine SCNT embryos than mSOF medium.

Effect of different culture media on the temporal gene expression in the bovine developing embryos

We have previously shown that the in vitro embryonic development and the yield of viable calves were increased by using a two-step chemically defined medium for post-fertilization culture of bovine embryos. In this study, we explored the embryonic development and the temporal behavioral interaction of the genes involved in IFNτ gene expression and how they behave in an orchestrated manner to increase the developmental competence of IVF produced embryos by culturing in the chemically defined medium. Behavior of genes included ETS2, CDX2, GATA2, GATA3, OCT4 and NANOG was analyzed in early bovine IVF produced embryos, (from compact morulae to the blastocyst hatching stages), by semi- and relative quantitative PCR and compared between two in vitro culture (IVC) systems, two-step chemically defined medium and modified synthetic oviductal fluid (mSOF) containing 8 mg/mL, BSA. Early embryonic development was found to be better in two-step chemically defined culture system than that of mSOF as indicated by the increment of blastocyst yield, 33.1% in two-step culture system vs 18.8% in mSOF medium, and the blastocyst hatching, 52.3% in two-step culture system vs 33.5% in mSOF medium. Relative quantitative gene expression showed harmonic behavior in the two-step culture system rather than the culture in mSOF, IFNτ showed even increase throughout the embryonic development in the two-step culture medium while it decreased with blastocyst hatching in mSOF culture condition. Temporal dominance of OCT4 over all the transcription factors was found in regulation of IFNτ expression (the major factor of expression regulation but in inverse manner). However, ETS2, CDX2, GATA2 and GATA3 are potent IFNτ stimulator in cumulative manner but in case of OCT4 decrement. CDX2 directly related with IFNτ, but still under OCT4 dominance and also regulated by the subservient of OCT4 which is NANOG. In conclusion, this study confirmed our previous results about the usefulness of using the two-step chemically defined culture medium for increasing the developmental competence of IVF produced embryos and elucidated the dominance of OCT4 over the other genes implicated in regulation of IFNτ expression.

45 IN VITRO DEVELOPMENT OF BOVINE TRANSGENIC NUCLEAR TRANSFER EMBRYOS IN SERUM-FREE AND SERUM-SUPPLEMENTED MEDIA

Novel serum-free media (IVD101) has been shown to be effective for the production of in vitro-produced embryos for subsequent implantation into cows (Hoshi 2003 Theriogenology 59, 675–685). The objective of the present study was to determine whether serum-free embryo cultivation during preimplantation stage could be used for the production of bovine transgenic nuclear transfer embryos. Somatic cell nuclear transfer (SCNT) embryos were produced by using donor cells containing a vector to induce the production of human erythropoietin in cow's milk. αS1-casein was selected as the promoter to be used in this study through the specific promoter activity test, and enhanced green fluorescent protein(EGFP) gene was attached to the CMV promoter to allow observation of the donor cell during the experiment. Adult fibroblast cells were transfected with lipofectamine. After G418 selection, the transfected cells were injected to the enucleated oocytes, and injected embryos were accomplished by cell-to-cell fusion. These embryos were then activated with calcium ionomycin and 6-dimethylaminopurine. The reconstructed embryos were cultured in IVD101 and mSOF media at 38.5°C, in a 5% CO2, 5% O2, and 90% N2 atmosphere. Embryos were cultured for 4 days, followed by addition of FBS in case of mSOF media. On day-7, the developmental ability and the number of cells in the reconstructed embryos were determined. Statistical analysis of embryo development data was carried out using unpaired t-test, or ANOVA. There were no significant differences in the cleavage rate (69.6 ± 3.2% v. 64.5 ± 5.0%), blastocyst rate (18.7 ± 1.3% v. 22.0 ± 1.6%), and cell number (113.9 ± 7.5 v. 103.6 ± 7.9) between IVD101 and mSOF+FBS cultured embryos. These results indicated that serum-free media did not reduce the developmental competence of SCNT embryos compared with serum-supplemented media. Further studies are required to investigate whether this serum-free transgenic embryo cultivation could be used for developmental potential in terms of full-term development after embryo transfer.

33 PRODUCTION OF CLONED BOER GOATS AND DORPER SHEEP IN ARGENTINA

Somatic cell nuclear transfer (SCNT) has been proposed as an outstanding tool for expanding the dissemination capacity of animals of extreme genetic value, as well as for the genetic resurrection of elite animals affected by incurable disease or that died suddenly. Numbers of outstanding males of meat-specialised breeds of goats (Boer) and sheep (Dorper) recently imported into Argentina were expanded using SCNT technology. Oocytes were collected by laparoscopic ovum pickup (LOPU) from 40 Raza Criolla goats and 38 crossbreed sheep that were hormonally stimulated, as described previously (Baldassarre et al. 2002 Theriogenology 57, 275). Oocyte maturation, cell transfer, fusion and activation, culture, and transfer to recipients were conducted following procedures previously described (Baldassarre et al. 2003 Cloning Stem Cells 5, 279). Briefly, oocytes were matured in vitro for 24 h in TCM 199 supplemented with hormones and 10% serum, at 38.5°C and 5% CO2. 2 caprine fetal fibroblast cell lines (FF1 and FF2) were established from purebred Boer fetuses generated by selective breeding of elite animals, while a fibroblast ovine line was established from a skin biopsy from an elite Dorper ram. Cells were transferred into previously enucleated oocytes, followed by electric fusion using a single DC pulse of 1.6 kV cm–1 for 70 μs. Finally, the reconstructed embryos were activated using ionomycin (5 μM/5 min) followed by cycloheximide (10 μg mL–1) and cytochalasin B (7.5 μg mL–1) for 4 to 5 h, followed by in vitro culture in mSOF media before transfer into the oviducts of synchronized recipients within 24 h after fusion. An average of 10.4 and 12.8 reconstructed embryos were transferred to each of 21 and 12 recipient goats and sheep, respectively. Pregnancy was detected and monitored for the first 3 months by transrectal ultrasound scanning. Initial pregnancy (4 recipients, 33%) was maintained from gestation Day 30 to term in sheep, while goats exhibited a dramatic drop from 9 recipients pregnant (41%) on Day 30 to only 2 (9%) giving birth. Deliveries were by elective C-section. The number of normal offspring with good postpartum survival was 2/2 in goats (100%) and 3/5 (60%) in sheep. Substantial differences were observed between the 2 cell lines used in goats, where pregnancy was 4/11 (36%) for FF1 and 5/10 (50%) for FF2 at Day 30; however, only 2 goats carrying FF2 pregnancies carried. These results are in agreement with previous reports suggesting that cell line may be the largest source of result variation in SCNT. At the time of writing this abstract these clones are ∼4 months of age, healthy and growing normally (&gt;40 kg weight). To the best of our knowledge, these are the first cloned goats produced by SCNT technology in Latin America, and the second group to produce cloned sheep in the region.

30 SCRIPTAID TREATMENT IMPROVES POST-IMPLANTATION DEVELOPMENT OF SHEEP CLONED EMBRYOS

Increased histone acetylation by exposure to inhibitors of deacetylase enzymes has been reported to improve development of embryos produced by somatic cell nuclear transfer (SCNT). However, the response to such treatment seems to vary according to the species, cell line, and type of inhibitor used. The main objective of this study was to evaluate if treatment with the histone deacetylase inhibitor Scriptaid could improve the development to term of sheep SCNT-embryos. The 2 fibroblast cell lines used in this study were obtained from skin biopsies collected from 2 adult rams of the Santa Ines breed. Oocytes were collected by laparoscopic ovum pickup (LOPU) from 30 crossbred sheep that were hormonally stimulated as described previously (Baldassarre et al. 2002 Theriogenology 57, 275). Oocyte maturation, cell transfer, fusion and activation, culture and transfer to recipients were conducted following procedures previously described (Baldassarre et al. 2003 Cloning Stem Cells 5, 279). Briefly, oocytes were matured in vitro for 24 h in TCM 199 supplemented with hormones and 10% fetal bovine serum, at 38.5°C in 5% CO2. Cells were transferred into enucleated oocytes, followed by electric fusion using a single DC pulse of 1.6 kV cm–1 for 70 μs. The reconstructed embryos were then activated using ionomycin (5 μM/5 min) followed by cycloheximide (10 μg mL–1) and cytochalasin B (7.5 μg mL–1) for 4 to 5 h and then cultured in mSOF media (control); while half of the reconstructed embryos were exposed to 500 nM Scriptaid for 10 to 12 h starting after ionomycin treatment. Subsequent to culture in mSOF ± Scriptaid as above, selected embryos were finally transferred into the oviducts of synchronized recipients within 24 h from fusion. Pregnancy was detected and monitored for the first 3 months by transrectal ultrasound scanning. A total of 258 oocytes were recovered (8.6/donor), of which 203 resulted in fused embryos after micromanipulation (79%) and 178 (69%) were selected for transfer into the oviducts of 18 synchronized recipients (avg. 10 embryos/recipient). Initial pregnancy was significantly higher in the Scriptaid group (40 v. 12.5%; P &lt; 0.01). Interestingly, pregnancy was maintained through gestation Day 90 in the Scriptaid group, while the pregnant recipient carrying the control embryos lost her pregnancy by Day 60. All 4 pregnant recipients are due in early August. Our results are consistent with a previous report from (Zhao et al. 2010 Cel. Reprog. 12, 75) working with pig embryos and suggest that Scriptaid treatment can improve post-implantation development of SCNT sheep embryos. The results above will be further evaluated when data from births becomes available.

39 IN VITRO DEVELOPMENT OF CANINE EMBRYOS PRODUCED BY INTERSPECIES SOMATIC CELL NUCLEAR TRANSFER USING ENUCLEATED BOVINE OOCYTES

Interspecies somatic cell nuclear transfer (iSCNT) is an invaluable tool for studying nucleous-cytoplasm interactions, and may provide an alternative for cloning endangered animals, whose oocytes are difficult to obtain. Using readily available oocytes from domestic/farm animals as recipients for iSCNT would greatly benefit ongoing research on somatic cell reprogramming. However, little information is available concerning the development of canine iSCNT embryos reconstructed with bovine oocyte cytoplasm. In the first experiment, we investigated the influence of donor cell type on the development of canine iSCNT embryos reconstructed with enucleated bovine oocytes. Canine mammary gland tumour (MGT) cells and cumulus cells were used as donor cell. The bovine oocytes matured for 22 h were enucleated by the micromanipulator, and the donor cells were transferred into the perivitelline space adjacent to the plasma membrane of the oocyte. The couples were fused and activated simultaneously with a single DC pulse of 2.3 kV cm–1 for 30 μs, using an electro cell fusion generator. The reconstructed embryos were cultured for 72 h in the mSOF medium supplemented with 0.4% BSA. After 72 h of culture, only cleaved embryos were further co-cultured with bovine cumulus cells in mSOF supplemented with 5% fetal bovine serum (FBS) for an additional 5 days. In the second experiment, we examined the effects of serum type on the development of canine iSCNT embryos. The embryos reconstructed with canine cumulus cells were co-cultured with canine cumulus cells in mSOF supplemented with 5% FBS, and canine oestrous and diestrous serum for 5 days after 72 h of culture with 0.4% BSA. Data were analysed by chi-square analysis with a Yates’ correction. More than 75% of the canine somatic cells successfully were fused with bovine enucleated oocytes following electrofusion, irrespective of the types of the donor cells. There were no significant differences in the cleavage rates of iSCNT embryos between the cumulus cell and MGT cell (66.2% v. 62.6%). Although none of the embryos reconstructed with MGT cells (n = 123) developed to the 16-cell stage, 6% of embryos with cumulus cells (n = 133) reached at least the 16-cell stage. There were no significant differences in the cleavage rates of iSCNT embryos among the types of serum. The iSCNT embryos could not develop to the blastocyst stage, irrespective of the type of donor cell and serum. In conclusion, our results indicate that the bovine oocytes partly supported the remodelling and reprogramming of the canine somatic cell nuclei, but they were unable to support the development to the blastocyst stage of canine iSCNT embryos. Moreover, the development to the late embryonic stage of iSCNT embryos may be influenced by the type of donor cell but not serum.

Stimulatory effect of Rho-associated coiled-coil kinase (ROCK) inhibitor on revivability of in vitro-produced bovine blastocysts after vitrification

Inhibition of Rho-associated coiled-coil kinase (ROCK) activity promoted recovery and growth of frozen-thawed human embryonic stem cells. The primary objective was to determine if a ROCK inhibitor (Y-27632) in post-thaw culture medium improved revivability of vitrified IVP bovine blastocysts. Expanding or expanded blastocysts (7 d after IVF) were vitrified (minimum volume cooling procedure, using a Cryotop) in 15% ethylene glycol, 15% DMSO and 0.5 M sucrose. When post-warm blastocysts were cultured in mSOF medium, survival rate (re-expansion of blastocoel at 24 h of culture) was improved ( P < 0.05) by the addition of 10 μM Y-27632 (94.9 ± 2.4%, mean ± SEM) compared to a control (78.0 ± 6.0%). Conversely, after 48 h of culture, there were no significant differences in hatching rate (62.8 ± 11.1 vs. 59.6 ± 9.4%) and mean total cell number (135.2 ± 13.1 vs. 146.7 ± 13.3). In non-vitrified IVP bovine blastocysts, the hatching rate on Day 9 was improved by Y-27632 (91.7 ± 3.8 vs. 54.7 ± 8.9%, P < 0.05), with no difference in mean total cell number of blastocysts (230.0 ± 23.0 vs. 191.2 ± 22.2, P = 0.23). In an additional experiment, Y-27632 was added to culture medium on either Day 0, Day 2, or Day 4 (and remained present until Day 8), resulting in no improvement in blastocyst yield compared to a control group (7.5 ± 2.1, 31.4 ± 2.3, 36.2 ± 3.2, and 28.6 ± 6.9%, respectively). In conclusion, adding a ROCK inhibitor to post-thaw culture medium improved revivability of IVP bovine blastocysts after vitrification and warming.

İn Vitro Köpek Embriyosu Üretimi Üzerine İki Farklı Medyumun Etkisi

Summary Embryo production via in vitro fertilization and nuclear transfer has been accomplished in the dog, and the transfer of the cloned embryos has recently resulted in the birth of puppies. However, the efficiency of these technologies is still very limited. Until now, only two morulas and single blactocyst have been achieved in vitro. Therefore, the aim of the present study was to examine the effects of two different media (mSOF and TCM 199) on in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC) of immature dog oocytes. The study was performed in two steps. At the first step, the effects of two different media, on IVM of dog oocytes were investigated. At the end of the IVM period, the nuclear maturation rates were evaluated by aceto-orcein staining method. At the second step, after the IVM period the oocytes inseminated with fresh spermatozoa for 24 h and left for IVC for 7 d. At the end of the IVC period, embryonic development was assessed by microscopic observation at 24 h intervals and then fixed and stained by the same method. Consequently, maturation rates of oocytes in mSOF medium were significantly higher than those of the TCM 199 (P<0.001). After 7 d of the IVC period, only one oocyte was cleaved in the TCM 199, while eight oocytes cleaved and one of them developed to morula stage in mSOF medium group (P=0.037).

211 IN VITRO PRODUCTION OF SWAMP BUFFALO EMBRYOS BY INTRACYTOPLASMIC SPERM INJECTION: EFFECT OF CHEMICAL ACTIVATION TREATMENTS

Intracytoplasmic spern injection (ICSI) in the buffalo has not yet been well examined. Several factors involved affect the success rates of this technique, particularly the postinjection activation procedure. The objective of this study was to evaluate the effects of chemical activation treatments on in vitro development of oocytes after ICSI. A single spermatozoa was injected into the cytoplasm of an in vitro-matured oocyte using a micromanipulator under an inverted microscope. The ICSI oocytes were assigned to the following chemical activation treatments: (1) exposed to 5 μm ionomycin (Io) in Emcare medium for 5 min and placed in Emcare medium for 3 h, or (2) exposed to 7% ethanol (EtOH) in Emcare medium for 5 min and placed in Emcare medium for 3 h. The treated oocytes that extruded a second polar body were then selected and cultured either in (A) 1.9 mm 6-dimethylaminopurine (6-DMAP) in mSOF medium for 3 h, or (B) 10 μg mL–1 of cychloheximide (CHX) for 5 h. The treated oocytes were further cultured in mSOF medium supplemented with 3 mg mL–1 of fatty acid-free BSA at 38.5°C under a humidified atmosphere of 5% O2, 5% CO2, and 90% N2 for 2 d. Thereafter, 8-cell-stage embryos were selected and co-cultured with buffalo cumulus cells in mSOF medium at 38.5°C under a humidified atmosphere of 5% CO2 in air for another 5 d. The medium was changed daily and the development of embryos was recorded at the same time the medium was changed. The sham-injected oocytes were treated and cultured along with ICSI oocytes. With 8 replications for each activation treatment, 336 oocytes were used for ICSI. With 6 replications for each activation treatment, 211 oocytes were used for sham injection. The cleavage of ICSI oocytes treated with Io + 6-DMAP, EtOH + 6-DMAP, and EtOH + CHX was 76.2, 69.4, and 78.3%, respectively, which was significant higher (P &lt; 0.01) than ICSI oocytes treated with Io + CHX (52.4%) and also significant higher (P &lt; 0.01) than sham-injected oocytes in all treatments. The highest blastocyst rate was observed in ICSI oocytes treated with Io + 6-DMAP (28.6%), which was not significantly different from ICSI oocytes treated with EtOH + CHX (24.4%). The blastocyst rates of ICSI oocytes treated with Io + 6-DMAP and EtOH + CHX were significantly higher than ICSI oocytes treated with Io + CHX (5.9%) and EtOH + 6-DMAP (16.5%) and also were significantly higher than sham-injected oocytes in all treatments. In conclusion, our study demonstrated that activated ICSI of swamp buffalo oocytes with Io + 6-DMAP or EtOH + CHX gave the highest cleavage and blastocyst rates. This work was supported by the Thailand Research Fund and Suranaree University of Technology.

Improvement of canine somatic cell nuclear transfer procedure

The purpose of the present study on canine somatic cell nuclear transfer (SCNT) was to evaluate the effects of fusion strength, type of activation, culture media and site of transfer on developmental potential of SCNT embryos. We also examined the potential of enucleated bovine oocytes to serve as cytoplast recipients of canine somatic cells. Firstly, we evaluated the morphological characteristics of in vivo-matured canine oocytes collected by retrograde flushing of the oviducts 72 h after ovulation. Secondly, the effectiveness of three electrical strengths (1.8, 2.3 and 3.3 kV/cm), used twice for 20 micros, on fusion of canine cytoplasts with somatic cells were compared. Then, we compared: (1) chemical versus electrical activation (a) after parthenogenetic activation or (b) after reconstruction of canine oocytes with somatic cells; (2) culture of resulting intergeneric (IG) embryos in either (a) mSOF or (b) TCM-199. The exposure time to 6-DMAP was standardized by using bovine oocytes reconstructed with canine somatic cells. Bovine oocytes were used for SCNT after a 22 h in vitro maturation interval. The fusion rate was significantly higher in the 3.3 kV/cm group than in the 1.8 and 2.3 kV/cm treatment groups. After parthenogenesis or SCNT with chemical activation, 3.4 and 5.8%, respectively, of the embryos developed to the morula stage, as compared to none of the embryos produced using electrical activation. Later developmental stages (8-16 cells) were transferred to the uterine horn of eight recipients, but no pregnancy was detected. However, IG cloned embryos (bovine cytoplast/canine somatic cell) were capable of in vitro blastocyst development. In vitro developmental competence of IG cloned embryos was improved after exposure to 6-DMAP for 4 h as compared to 0, 2 or 6h exposure, although the increase was not significantly different among culture media. In summary, for production of canine SCNT embryos, we recommend fusion at 3.3 kV/cm, chemical activation, culture in mSOF medium and transfer of presumptive zygotes to the oviduct of recipient animals. The feasibility of IG production of cloned canine embryos using bovine cytoplasts as recipient of canine somatic cells was demonstrated.

Goat Embryo Development from in vitro Matured Oocytes of Heterogeneous Quality Through Intracytoplasmic Sperm Injection Technique

Experiments were conducted to develop an intracytoplasmic sperm injection (ICSI) protocol to produce goat embryos from in vitro matured heterogeneous oocytes. Two different protocols ('Protocol 1' or P-1 and 'Protocol 2′ or P-2) were formulated and tested to develop a suitable one. Cumulus-oocyte complexes (COCs) were obtained either by LOPU (P-1) or by ovariectomy and slicing (P-2). Recovered COCs were cultured in a microdrop (50 μL) of HEPES-buffered in vitro maturation (IVM) medium with 10% oestrus goat serum (OGS) (P-1) or IVM medium without HEPES with 15% OGS (P-2) in presence of CO2(5%) at 38.5°C either for 24 h (P-1) or 27 h (P-2). After IVM, COCs were denuded to select a mature oocyte (Mil) and held in the incubator in presence of CO2 (5%) until ICSI. Motile sperm were selected from frozen-thawed buck semen by swim-up either in mDM (P-1) or mSOF (P-2) medium. A motile sperm was immobilized and injected, head-first, into the ooplasm of a MII oocyte. Sham injections were also performed as control. Injected oocytes were cultured in mSOF medium either with 10% (P-1) or 20% (P-2) goat serum in presence of CO2 (5%) at 38.5°C A significantly higher (p<0.01) number of COCs was recovered with P-2 (17.5 COCs/donor) than P-1 (6.7 COCs/donor). However, the quality of the COCs was better with P-1 than P-2. A higher proportion of COCs were matured with P-2 (69.3%) than P-1 (55.5%), which was not statistically significant. A fertilization rate of 28.6% was obtained in P-1 without any cleavage. Fertilization rate (54.1 %) was significantly higher (p<0.05) in P-2 with a cleavage rate of 18.2% and few morula-stage embryos were obtained (2.9%). In conclusion, better fertilization and embryo development rates were obtained with P-2 than P-1. Morula-stage embryos were obtained using ICSI technique from in vitro matured heterogeneous goat oocytes without any artificial activation and first reported in Malaysia. © 2007 Asian Network for Scientific Information.

38 EFFECTS OF TRICHOSTATIN A ON DNA METHYLATION IN CLONED BOVINE EMBRYOS

Recently, the efficiency of full-term development of somatic cloned mouse embryos was significantly increased by treatment with trichostatin A (TSA), an inhibitor of histone deacetylase (Kishigami et al. 2006 Biochem. Biophys. Res. Commun. 340, 183–189; Rybouchkin et al. 2006 Biol. Reprod. 74, 1083–1089). We have shown that TSA treatment improved the rate of development of the cloned bovine embryos to the blastocyst stage (Iwamoto et al. 2007 Reprod. Fertil. Dev. 19, 142 abst). Higher levels of DNA methylation have been shown in early cloned bovine embryos than in in vitro-fertilized (IVF) embryos (Dean et al. 2001 Proc. Nat. Acad. Sci. USA 98, 13734–13738; Santos et al. Curr. Biol. 13, 1116–1121). In this study, we examined the effects of TSA on DNA methylation levels in cloned bovine embryos by immunostaining with an antibody to 5-methyl cytosine (5-MeC). Bovine fibroblasts were cultured under serum starvation (0.4% FCS) for 7 days before they were used as donor cells. The cells were electrofused with bovine enucleated matured oocytes, and activated with a calcium ionophore and cycloheximide. Atotal of 131 cloned embryos were produced. The NT embryos were exposed to 0 (control) and 50 nmTSA from the start of activation to 48 h post-activation (hpa). They were then cultured in an mSOF medium. At 60 hpa, only embryos developed to the 8-cell stage were used for assessment of DNA methylation levels. Sixteen TSA-treated, 22 non-treated, and 19 IVF embryos were immunostained with 5-MeC antibody. For quantitative analysis of the DNA methylation levels, 5-MeC signals in the fluorescent images were determined using an image analyzer system (Aqua Cosmos; Hamamatsu Photonics, Shizuoka, Japan). The data were analyzed with Tukey-Kramer post hoc test for multiple comparisons following ANOVA. Relative levels of DNA methylation of TSA-treated cloned and IVF embryos did not differ (P &gt; 0.05), but were lower than those of non-treated cloned embryos (P &lt; 0.05). The results indicate that TSA treatment of cloned bovine embryos leads to a reduction of DNA methylation levels of their genome. The data suggest that the TSA treatment decreased the DNA methylation levels of cloned bovine embryos to the levels of IVF embryos, resulting in improved blastocyst development of the cloned embryos.