60 INFLUENCE OF HOECHST STAINING FOR NUCLEAR TRANSFER ON PARTHENOGENETIC EMBRYOS IN CYNOMOLGUS MONKEYS (MACACA FASCICULARIS)

2008 ◽  
Vol 20 (1) ◽  
pp. 111
Author(s):  
H. Tsuchiya ◽  
C. Iwatani ◽  
J. Okahara-Narita ◽  
J. Yamasaki ◽  
R. Torii

Nonhuman primates are valuable animal models for the study of human diseases, and somatic cell nuclear transfer (SCNT) is an important method for establishing tailor-made embryonic stem (ES) cells and transgenic animals in these model species. However, there have been few reports on SCNT in nonhuman primates. Moreover, the development of cloned blastocysts could be influenced by any chemical reagents and manipulations used in this technique. In this study we compared blastocyst developmental rates with and without Hoechst staining. Metaphase II (MII) oocytes were collected from hormone-treated adult female cynomolgus monkeys (Macaca fascicularis) under laparoscopic observation (Torii et al. 2000 Primates 41, 39–47). A pseudo-SCNT procedure, which consisted of cytochalasin B treatment, cytoplasm removal, and dissection of the oocyte membrane, was performed on MII oocytes either in the presence of (Experiment 1; Ex1) or in the absence of Hoechst 33342 (Experiment 2; Ex2). Hoffman modulation contrast microscopy was used in Ex1 and Nomarski differential interference contrast (DIC) was used in Ex2. In Ex1, cumulus-free MII oocytes were treated with Hoechst 33342 (5 mg mL–1; Sigma Chemical Co., St. Louis, MO, USA) for 5 min and the following pseudo-SCNT procedure was carried out: cytochalasin B (CB, 5 µg mL–1; Sigma) for 20 min, removal of a small amount of cytoplasm (pseudo-EN), and then dissection of the oocyte cytoplasmic membrane (pseudo-IN) under Hoffman modulation contrast microscopy. In Ex2, CB treatment, pseudo-EN, and pseudo-IN were performed under Nomarski DIC microscopy. After treatment, these oocytes were activated by parthenogenetic stimulation. Parthenogenesis was induced by 5-m ionomycin (Sigma) for 2 min and 2 mm 6-dimethylaminopurine (Sigma) for 4 h. As a control, cumulus-free MII oocytes were activated by only parthenogenetic stimulation, without the above manipulations. These activated oocytes were cultured in CMRL-1066 medium containing 20% calf serum at 38�C in 5% CO2, 5% O2, and 90% N2 for 7–8 days. The rates of development to blastocyst stage were 14% (1/7) in Ex1, 30% (3/10) in Ex2, and 29% (2/7) in the control. The developmental rate of parthenotes to the blastocyst stage in Ex2 was greater than that in Ex1 and similar to the control. These results suggest that treatment of cynomolgus monkey oocytes with Hoechst staining possibily decreases development to the blastocyst stage. Therefore, enucleation under Nomarski DIC will be a good alternative to Hoechst staining and could improve the potential development of nonhuman primate SCNT embryos.

2005 ◽  
Vol 17 (2) ◽  
pp. 180
Author(s):  
R. Ribas ◽  
B. Oback ◽  
J. Taylor ◽  
A. Maurício ◽  
M. Sousa ◽  
...  

Mice have been cloned from somatic and embryonic cells; however, only 0–3% of the reconstructed embryos develop into viable offspring. In addition, the piezo microinjection method widely used for mouse nuclear transfer (NT) is difficult to master. Our objective was to compare cumulus and ES cells as nuclear donors using a simplified method of zona-free NT. In cattle, zona-free NT is simpler, faster, easier to learn and more reproducible than zona-intact NT (Oback et al. 2003 Cloning Stem Cells 5, 3–12). Oocytes were recovered at metaphase II stage (13 h after hCG injection) from the oviducts of C57BL/6J × DBA/2 F1 females (8–10 weeks of age). Cumulus cells were removed with hyaluronidase (300 units/mL) and the zona pellucida digested with pronase (0.5%) at 37°C for 3 min. Oocytes were then enucleated under UV light in cytochalasin B (5 μg/mL) after a 5-min staining with Hoechst (5 μL/mL). The metaphase DNA was removed in an enucleation pipette (16–20 μm, perpendicular break) by separating karyoplast and cytoplast with a simple separation pipette (60–80 μm, perpendicular break, closed round tip). Embryonic stem (ES) cells were cultured for 3 days and serum-starved for 16 h before use. Cells from this line had yielded offspring by the piezo procedure. Cumulus cells were used freshly. Donor cells were attached to the cytoplasts with phytohemagglutinin (10 μg/mL) and couplets were electrically fused in 0.2 mM mannitol buffer. Reconstructed embryos were activated 1–2 h after fusion for 5–6 h in CZB medium containing 10 mM strontium chloride and 5 μg/mL of cytochalasin B. Embryos were cultured individually in 5-μL droplets in CZB. Morulae and blastocysts were transferred into the uteri (Day 2.5) of pseudopregnant surrogate mothers (C57BL/6J × CBA/2J). Recipient mothers were sacrificed at 19.5 days postcoitum and pups removed. Airways were cleaned to remove fluid and the pups were held in a warm box before being fostered by a lactating mother. During development of the technique, we assessed the frequency of fusion, cleavage of reconstructed embryos, and development to morula/blastocyst stage. Fusion (58.1 ± 6.7% vs. 24.2 ± 1.7%, P < 0.001) and cleavage (66.4 ± 4.2% vs. 50.5 ± 5.4%, P < 0.05), all respectively, were higher when cumulus cells were used as donors, as compared with ES cells. However, the percentage of embryos developing to morula/blastocyst stage was greater when ES cells were used (22.2 ± 4.2% vs. 5.3 ± 2.7%, P < 0.01). Using ES cells as donors, 19/94 (20.2%) reconstructed embryos reached compacted morula/blastocyst stage. After transfer to five recipients, one pup was born (5.2%). It was larger and heavier than uncloned pups of the same age. The pup is healthy and now 12 weeks old. Genotype was confirmed by microsatellite analysis. The birth of a healthy cloned mouse pup from zona-free NT provides “proof of principle” of a technology that promises to increase throughput, ease of operation, and reproducibility of mouse cloning.


Primates ◽  
2007 ◽  
Vol 48 (3) ◽  
pp. 232-240 ◽  
Author(s):  
Junko Okahara-Narita ◽  
Hideaki Tsuchiya ◽  
Tatsuyuki Takada ◽  
Ryuzo Torii

2018 ◽  
Vol 30 (7) ◽  
pp. 1002 ◽  
Author(s):  
Qing Guo ◽  
Long Jin ◽  
Hai-Ying Zhu ◽  
Xiao-Xu Xing ◽  
Mei-Fu Xuan ◽  
...  

In this study we examined the effects of JNJ-7706621, a cyclin-dependent kinase inhibitor, on the in vitro growth of pig embryos that had been produced either by parthenogenetic activation (PA) or somatic cell nuclear transfer (SCNT). A significantly higher percentage of PA embryos reached the blastocyst stage by Day 7 after exposure to 10 µM JNJ-7706621 for 4 h compared with embryos exposed to 5 µg mL−1 cytochalasin B for 4 h (P < 0.05). Similarly, the rate of Tyr15 phosphorylation of the complex of cyclin and p34cdc2 (CDK1) was significantly elevated in the JNJ-7706621-treated embryos compared with embryos exposed to cytochalasin B or non-treated controls (P < 0.05). In contrast, Thr161 phosphorylation of CDK1 was significantly lower in the JNJ-7706621-treated group compared with the cytochalasin B-treated as well as the non-treated group (P < 0.05). Similarly, the level of M-phase-promoting factor (MPF) in embryos was significantly lower in the JNJ-7706621-treated group compared with the cytochalasin B-treated and non-treated groups (P < 0.05). In addition, more SCNT embryos reached the blastocyst stage after treatment with JNJ-7706621 than following exposure to cytochalasin B (P < 0.05). In conclusion, these results reveal that exposure to 10 µM JNJ-7706621 for 4 h improves early development of PA and SCNT porcine embryos by suppressing the activity of CDK1 and a concomitant reduction in the level of MPF.


2008 ◽  
Vol 20 (1) ◽  
pp. 102
Author(s):  
J. Liu ◽  
M. E. Westhusin ◽  
D. C. Kraemer

Somatic cells in semen could be a valuable source of nuclei for cloning animals by somatic cell nuclear transfer, especially when other ways of obtaining somatic cells are not available. The usefulness of the cells cultured from bovine semen for nuclear transfer was evaluated in the present study. Twelve ejaculates were collected from nine bulls representing three breeds: Charolais, Brahman, and a crossbreed rodeo bull. All of the samples were processed immediately, and somatic cells were isolated by centrifuging through 20%, 50%, and 90% percoll columns (Nel-Themaat et al. 2005 Reprod. Fertil. Dev. 17, 314–315). Somatic cell lines were obtained from 7 of the 12 ejaculates. These cell lines have classic epithelial morphology, express cytokeratin and vimentin, and proliferate well in the medium we previously designed for the epithelial cells in ovine semen (Jie Liu et al. 2007 Biol. Reprod. special issue, 177–178). Cell lines from three bulls that had been cultured in vitro for 1–2 months were used in the cloning experiments. Bovine ovaries were collected from a local slaughterhouse and transported to the laboratory in warm saline solution within 2–4 h. Compact cumulus–oocyte complexes with evenly distributed cytoplasm were selected and matured for 18 h at 38.5�C with 5% CO2 in humidified air. Cumulus cells were removed by pipetting in 0.3% hyaluronidase solution (Sigma Chemical Co., St. Louis, MO, USA) for 5 min. Oocytes were selected for the presence of a first polar body and stained in 5 µg mL–1 Hoechst 33342 (Sigma) and 5 µg mL–1 cytochalasin B (Sigma) for 10–15 min before enucleation. Successful enucleation was confirmed by brief exposure of the oocytes to ultraviolet light. Epithelial cell lines cultured to 90–100% confluence were trypsinized, and a single cell was inserted into the perivitelline space of an oocyte. Fusion was induced by applying two 1.8–1.9 kV cm–1, 20 µs direct-current pulses delivered by an Eppendorf Multiporator (Eppendorf, North America) in fusion medium comprising 0.28 m Mannitol (Sigma), 0.1 mm CaCl2 (Sigma), and 0.1 mm MgSO4 (Sigma). One and half to 2 h post fusion, activation was induced by applying two 0.3 kV cm–1, 55 µs direct-current pulses in the fusion medium, followed by incubation in 10 µg mL–1 cycloheximide (Sigma) and 5 µg mL–1 cytochalasin B for 5 h in a humidified 5% CO2, 5% O2, and 90% N2 gas mixture at 38.5�C. The embryos were washed three times and cultured in commercially available G1/G2 medium (Vitrolife, Inc., Englewood, CO, USA) for up to 10 days. Blastocyst development rates using somatic cells from three of the bulls, 1-year-old Charolais, 6-year-old Brahman, and 8-year-old Brahman, were 15.9% (18/113), 34.5% (29/84), and 14.4% (13/90) of the fused one-cell embryos, respectively. Of these blastocyst stage embryos, 38.9% (7/18), 72.4% (21/29), and 61.5% (8/13) hatched, respectively. The present study shows that epithelial cells cultured from bovine semen can be used to produce blastocyst-stage embryos by somatic cell nuclear transfer.


2008 ◽  
Vol 20 (1) ◽  
pp. 197
Author(s):  
J. Zhu ◽  
K. H. S. Campbell

The objective of the present experiments was to examine whether strontium could activate in vitro-matured ovine oocytes. Oocytes were collected and matured as previously described (Lee and Campbell 2006 Biol. Reprod. 74, 691–698). Briefly, selected cumulus–oocyte complexes were cultured in modified TCM-199 medium supplemented with 20% sheep serum and hormones for 22–23 h, at 39°C, 5% CO2 in air. Matured oocytes were randomly divided into four groups and treated as follows: (1) cultured in 10 mm strontium + 5 μg mL–1 cytochalasin B in Ca2+-free CZB medium for 4–5 h; (2) electrically activated in Ca2+-containing medium, then cultured in 10 mm strontium + 5 μg mL–1 cytochalasin B in Ca2+-free CZB medium for 4–5 h; (3) electrically activated in Ca2+-containing medium and then cultured in SOF medium containing 5 μg mL–1 cytochalasin B for 4–5 h; and (4) electrically activated in Ca2+-free medium and then transferred into SOF medium + 5 μg mL–1 cytochalasin B for 4–5 h. This experiment was repeated three times. Activation rates based on the number of pronuclear formations/the number of oocytes cultured were 96.7% (147/152), 95.9% (116/121), 75.9% (101/133), and 43.0% (56/107) in Groups 1–4, respectively. After 7 days of culture in SOF medium, 26.8%, 33.3%, 19.6%, and 0% of oocytes in Groups 1, 2, 3, and 4 developed to the blastocyst stage, respectively. Significant differences in blastocyst rate were observed across these groups except between groups 1 and 2 (P < 0.01). However, there were no significant differences in mean number of nuclei/blastocyst across Groups 1, 2, and 3 (P > 0.05). Our results demonstrated that in vitro-matured ovine oocytes can be effectively activated with strontium alone, resulting in an activation rate of 96.7% and a blastocyst rate of 26.8% (blastocysts/oocytes). Also, a combination of strontium and electrical pulses could benefit sheep oocyte activation and embryo development to the blastocyst stage (95.9% and 33.3%, respectively). We conclude that strontium is an effective activator for sheep oocyte activation and it could be used for sheep nuclear transfer. Table 1. Parthenogenetic development of oocytes activated by SrCl2+ and electrical pulses


2008 ◽  
Vol 20 (1) ◽  
pp. 196 ◽  
Author(s):  
C. Wang ◽  
K. Lee ◽  
S. Koh ◽  
Z. Machaty

Cloning domestic cats is useful in comparative medicine programs as it may provide insight into unique disease mechanisms and facilitate investigation of new therapeutic options. It is also believed to be beneficial for the conservation of precious animal models. However, as in many species, low birth rates after nuclear transfer remain a formidable challenge. One potential reason for the low efficiency is poor embryo development following activation of the reconstructed oocytes. The number of methods available to induce a transient increase in the oocytes' cytosolic free calcium level to stimulate development is rather limited. Although strontium has been reported to successfully activate the developmental program of mature mouse and rat oocytes, it was without effect in all other species studied. Here we investigated the effect of strontium on mature cat oocytes. Oocytes collected from the cat ovaries were matured in vitro in Feline Optimized Culture Medium (FOCM) supplemented with 0.6 mm cysteine, 0.1 mm cysteamine, 1 IU mL–1 eCG, 2 IU mL–1 hCG, 25 ng mL–1 epidermal growth factor (EGF) for 24 h. For intracellular calcium measurements, mature oocytes were incubated in the presence of 2 µ m fura-2Am, a calcium indicator dye, and 0.02% pluronic F-127 for 40 min. Individual oocytes were transferred into calcium-free HEPES, and SrCl2 was added to the medium at a final concentration of 20 mm. Changes in the intracellular free calcium levels were then monitored using an InCyt Im2™ fluorescence imaging system (Intracellular Imaging, Cincinnati, OH, USA). Preimplantation embryonic development was also evaluated by incubating the oocytes with 20 mm SrCl2 in calcium-free HEPES medium supplemented with 7.5 µg mL–1 cytochalasin B for 6 h. Control oocytes were activated by two 20-µs-long, 100 kV cm–1 direct current pulses and incubated in the presence of 7.5 µg mL–1 cytochalasin B for 6 h. After activation, the oocytes were cultured in FOCM for 6 days. At the end of the culture period, embryonic development was recorded; the nuclear number of the embryos was also determined after staining with Hoechst 33342. Data were subjected to one-way ANOVA, and differences between treatments were analyzed using the Tukey test. We found that strontium triggered a transient rise in the intracellular free calcium concentration in all oocytes tested (N = 20). Strontium treatment also induced cleavage in 49.7% (92/185) of the oocytes, while 4.9% (9/185) of the activated oocytes developed to the blastocyst stage. In the electroporated group, cleavage frequency was 57.1% (104/182) and blastocyst formation was 8.8% (16/182). Data analysis showed that there was no significant difference between the two groups in terms of cleavage frequency and blastocyst formation. This is the first study to demonstrate that strontium can induce cytoplasmic calcium increase in cat oocytes and trigger development up to the blastocyst stage. The results also indicate that SrCl2 may be useful for oocyte activation during cat nuclear transfer. Additional studies are needed to determine whether SrCl2 can trigger development more effectively than current activation techniques.


Reproduction ◽  
2001 ◽  
pp. 49-60 ◽  
Author(s):  
T Wakayama ◽  
R Yanagimachi

Cloning methods are now well described and in almost routine use. However, the frequencies of production of live offspring from activated oocytes remain at < 3% and little is known about the factors that affect these frequencies. The effects of cytokinesis inhibitors, dimethylsulphoxide (DMSO) and the cell cycle of recipient cytoplasm on the cloning of mice were examined. Reconstructed oocytes, which were activated immediately after nucleus injection and cultured without cytochalasin B, developed into blastocysts at a frequency of 30--54% and into live cloned offspring at a frequency of 2--3%. Activated zygotes did not support development to full term after nuclear transfer. Reconstructed oocytes were activated 1--3 h after nuclear transfer and were exposed separately to three inhibitors of cytokinesis (cytochalasin B, cytochalasin D or nocodazole) to examine the toxicity of these inhibitors on cloning. All of the oocytes exposed to nocodazole-containing media formed many small pseudo-pronuclei, whereas with cytochalasin-containing media most of the activated oocytes formed only two pseudo-pronuclei. Despite such differences, 42--61% of reconstructed embryos developed to the morula-blastocyst stage and 1--3% developed to full term in all groups. Addition of 1% (v/v) DMSO to the activation medium significantly improved the frequency of development to the blastocyst stage and full term; however, this improvement did not lead to a higher success rate in the generation of live cloned offspring. These results show that activated mouse oocytes/zygotes are not effective cytoplasmic recipients with the methods described and that the lack of success of cloning is not due to inhibition of cytokinesis.


2009 ◽  
Vol 21 (1) ◽  
pp. 128 ◽  
Author(s):  
N. A. Wani ◽  
J. A. Skidmore ◽  
U. Wernery

Experiments were conducted to study the in vitro development of reconstructed dromedary camel embryos after nuclear transfer by a modified zona-free method. Cumulus oocyte complexes, collected from slaughterhouse ovaries were cultured in TCM199 at 38.5°C in an atmosphere of 5% CO2 in air for 32 to 36 h. Matured oocytes were denuded of cumulus cells by repeated pipetting and the zona pellucida was removed by brief incubation in 5 mg mL–1 pronase dissolved in Ca- and Mg-free PBS. Zona-free oocytes were stained with 5 mg mL–1 Hoechst 33342 in H199 supplemented with 7.5 μg mL–1 cytochalasin B and 10% FCS. They were enucleated under constant UV-light exposure in H199 supplemented with cytochalasin B and 10% FCS. The granulosa cells at passage numbers 4 to 15 were used as nuclear donors. The zona-free cytoplasts were individually washed for a few seconds in 300 μg mL–1 of Phytohemagglutinin in H199, then quickly dropped on a single donor cell settled to the bottom of a drop of H199 with 0.5% FCS and pushed together with the mouth pipette. Couplets were electrically fused, at room temperature, with two DC pulses of 100 V cm–1 for 15 μs. Reconstructs were activated 2 h post-fusion, with 5 μm ionomycin for 3 min followed by culture in 6-diethylaminopurine for 4 h. The reconstructs were then cultured individually in either 5 μL drops under oil, in agar wells or in wells of wells (WOW) in a well of 4-well culture plate. Embryo culture medium consisted of TCM-199 supplemented with 0.15 mg mL–1 L-glutamine, 2.1 mg mL–1 sodium bicarbonate, 0.22 mg mL–1 pyruvate, 50 μg mL–1 gentamycine, 1% insulin-transferrin-selenium (ITS), and 15% estrous dromedary serum. The number of oocytes that had cleaved was recorded on day 2, whilst those developing to morulae and blastocysts were recorded on day 7 of culture. For cell count, the blastocysts were stained with Hoechst and cells counted under a fluorescent microscope at ×400. Data obtained was analysed by chi-square test. About 92% (349/380) of the oocytes were successfully enucleated and 76% (259/340) fused with the attached cells. The cleavage rate was significantly lower (P < 0.05) in reconstructed embryos cultured in droplets (10/72, 14%) as compared with those cultured in agar wells (37/87, 42%) or WOW system (42/96, 44%). The proportions of cleaved embryos reaching morula stage were 0, 83, and 89% in droplets, agar wells, and WOW, respectively. However, only 8% and 5% of the cleaved embryos developed to the blastocyst stage in the agar well and WOW culture systems, respectively. No difference was observed in the cell number of blastocysts produced in agar wells (77.3 ± 8.02) or WOW (78.0 ± 4.2) culture system. To the best of our knowledge, this is the first report of embryo production up to the blastocyst stage after NT in camelids and it shows that NT can be successfully applied for embryo production in camelids. Further studies are needed to optimize the parameters and to improve the efficiency for production of transferable blastocysts in this species. This study was kindly sponsored by H.H. General Sheikh Mohammed bin Rashid Al Maktoum, Ruler of Dubai.


Zygote ◽  
2012 ◽  
Vol 21 (4) ◽  
pp. 358-366 ◽  
Author(s):  
Takayuki Yamochi ◽  
Yuta Kida ◽  
Noriyoshi Oh ◽  
Sei Ohta ◽  
Tomoko Amano ◽  
...  

SummaryInterspecies somatic cell nuclear transfer (ISCNT) has been proposed as a technique to produce cloned offspring of endangered species as well as to investigate nucleus–cytoplasm interactions in mammalian embryo. However, it is still not known which embryo culture medium is optimal for ISCNT embryos for the nuclear donor or the oocyte recipient. We assessed the effects of the culture medium on the developmental competence of the ISCNT embryos by introducing cynomolgus monkey (Macaca fascicularis) fibroblast nuclei into enucleated rabbit (Oryctolagus cuniculus) oocytes (monkey–rabbit embryo). The monkey–rabbit ISCNT embryos that were cultured in mCMRL-1066 developed to the blastocyst stage, although all monkey–rabbit ISCNT embryos cultured in M199 were arrested by the 4-cell stage. When monkey–rabbit ISCNT and rabbit–rabbit somatic cell nuclear transfer (SCNT) embryos were cultured in mCMRL-1066, the blastocyst cell numbers of the monkey–rabbit ISCNT embryos corresponded to the cell numbers of the control rabbit–rabbit SCNT embryos, which were produced from a rabbit fibroblast nucleus and an enucleated rabbit oocyte. In addition, the presence of mitochondria, which were introduced with monkey fibroblasts into rabbit recipient cytoplasm, was confirmed up to the blastocyst stage by polymerase chain reaction (PCR). This study demonstrated that: (1) rabbit oocytes can reprogramme cynomolgus monkey somatic cell nuclei, and support preimplantation development; (2) monkey–rabbit ISCNT embryos developed well in monkey culture medium at early embryonic developmental stages; (3) the cell number of monkey–rabbit ISCNT embryos is similar to that of rabbit–rabbit SCNT embryos; and (4) the mitochondrial fate of monkey–rabbit ISCNT embryos is heteroplasmic from the time just after injection to the blastocyst stage that has roots in both rabbit oocytes and monkey fibroblasts.


2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Hong-Soo Lee ◽  
Da-Hee Kim ◽  
Sung-Hwan Kim ◽  
Min-Sung Kang ◽  
Han Na Suh

Abstract Background Nonhuman primates (NHPs) are superior model for ocular research due to its morphological and physiological similarities with humans. Thus, the effect of four different anesthetic combinations [ketamine (10 mg/kg), ketamine + xylazine (7 + 0.6 mg/kg), zoletil (4 mg/kg), and zoletil + xylazine (4 + 0.2 mg/kg)] on intraocular pressure (IOP) was determined in cynomolgus monkeys. Results The administration of ketamine + xylazine or zoletil + xylazine resulted in lower IOP compared to ketamine or zoletil alone. Moreover, the IOP in male monkeys was higher than in females. The difference between the right and left eye was not found. Conclusions Anesthetics affected the IOP, and gender differences should be considered when measuring the IOP of nonhuman primates (NHPs).


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