93 PRODUCTION OF LIVE PIGLETS BY CRYOPRESERVATION OF IN VITRO-PRODUCED PORCINE ZYGOTES

2008 ◽  
Vol 20 (1) ◽  
pp. 127
Author(s):  
T. Somfai ◽  
N. Kashiwazaki ◽  
M. Ozawa ◽  
J. Noguchi ◽  
H. Kaneko ◽  
...  

Successful cryopreservation of in vitro-produced porcine zygotes is reported in the present study. Follicular oocytes were collected from prepubertal gilts. They were matured (IVM), fertilized (IVF), and cultured (IVC) in vitro (Kikuchi et al. 2002 Biol. Reprod. 66, 1033–1041). Ten or 23 h after IVF, the oocytes were centrifuged at 10 000g at 37�C for 20 min to permit visualization of pronuclei. Zygotes with two or three pronuclei were selected under stereomicroscope and used for solid surface vitrification (SSV). Briefly, after equilibration in 4% ethylene glycol (EG) for 15 min, zygotes were washed in vitrification solution (35% EG, 5% polyvinyl pyrrolidone, and 0.3 m trehalose), and then dropped with about 2 µL vitrification solution onto the dry surface of aluminum foil floating on the surface of liquid nitrogen (LN2). Microdroplets were transferred into cryotubes and stored in LN2. During warming, vitrified droplets were transferred in warming solution (0.4 m trehalose) at 37�C for 1 min, and then consecutively transferred for 1-min periods into 0.2 m, 0.1 m, or 0.05 m trehalose solutions. Survival of vitrified/warmed zygotes was determined by their morphology. To assess their developmental competence, vitrified (SSV), cryoprotectant-treated (CT), and untreated (control) zygotes were cultured in vitro for 6 days. There was no difference in developmental competence between control and CT zygotes in terms of cleavage rates (88.1% and 86.1%, respectively), blastocyst rates (23.2% and 20.8%, respectively), and blastocyst cell numbers (38.0 � 2.0 and 41.2 � 1.7, respectively). The rate of live zygotes after SSV and warming was similar to that of the control (93.4% and 100%, respectively). Cleavage rates (71.7% and 86.3%, respectively) and blastocyst rates (15.8% and 24.5%, respectively) of SSV were significantly reduced after vitrification compared to control (P < 0.05, ANOVA). Blastocyst cell numbers of SSV and control embryos were similar (41.2 � 3.4 and 41.6 � 3.3, respectively). There was no difference in developmental ability between zygotes cryopreserved at an early (10 h after IVF) or late (23 h after IVF) pronuclear stage. When embryo culture medium was supplemented with 1 µm of the antioxidant glutathione, development of cryopreserved zygotes to the blastocyst stage did not differ significantly from that of the control zygotes (18.6% and 22.1%, respectively). To test their ability to develop to term, 150 vitrified zygotes were transferred into a recipient, resulting in pregnancy and the production of five live piglets. These data demonstrate that a high rate of porcine zygotes could be successfully cryopreserved at the pronuclear stage, preserving their full developmental competence.

2018 ◽  
Vol 30 (1) ◽  
pp. 179
Author(s):  
W. Choi ◽  
C. M. Owen ◽  
M. Barcelo-Fimbres ◽  
J. L. Altermatt ◽  
L. F. Campos-Chillon

Most in vitro-produced (IVP) bovine embryos are transferred fresh. Use of a HEPES/bicarbonate embryo culture medium for transportation would offer flexibility for embryo shipment and transfer. We hypothesized that embryos cultured for 36 (Day 6 embryos) or 60 h (Day 5 embryos) in a novel SCF1T medium (SOF for Conventional Freezing 1 supplemented with HEPES) would maintain developmental competence compared with bicarbonate-buffered medium SCF1 (control). In 5 replicates, IVP embryos were produced by aspirating cumulus–oocyte complexes (COC) from 2-to 8-mm follicles of abattoir ovaries. The COC (n = 1036) were matured for 23 h, fertilized with semen from 1 of 3 bulls, and cultured in SCF1 at 38.5°C, 5% CO2, 5% O2, and 90% N2 (Owen et al. 2017 Reprod. Fertil. Dev. 29, 129-130). Randomly, on Day 5 and 6 after fertilization, a subset of presumptive embryos were moved into 500-µL polystyrene vials containing 100 µL of SCF1T medium, covered with 300 µL of sterile mineral oil and cultured in a portable incubator (MicroQ iQ2, Scottsdale, AZ, USA) at 38.5°C for 60 and 36 h, respectively. On Day 7.5 post-fertilization, blastocyst rates were evaluated and embryos (n = 8) from each group were stained with 1 µg mL−1 Nile Red for lipid quantification, and 300 nM Mitotracker Red CMX-Rosamine (Thermo Fisher Scientific, Waltham, MA, USA) for mitochondrial polarity. Images were obtained with confocal microscopy and fluorescent intensity (AFU) was measured by Image J software (National Institutes of Health, Bethesda, MD, USA). Data were analysed by one-way ANOVA and means separated by Tukey’s HSD. Results (Table 1) indicate similar blastocyst rates and lipid content between embryos cultured for 36 to 60 h in SCF1T and control media (P > 0.05). However, mitochondrial polarity was lower in the Day 5 group (P < 0.05) compared with Day 6 and control groups. Results suggest that culturing embryos in SCF1T medium for 36 h maintains developmental competence compared with bicarbonate-buffered media and offers an alternative for shipment and transfer of IVP embryos. Studies involving evaluation of pregnancy rates of the present study are ongoing. Table 1.Effects of Day 5 or 6 SCF1T embryo culture medium on development, lipid content, and mitochondrial polarity


2006 ◽  
Vol 18 (2) ◽  
pp. 250
Author(s):  
M. G. Marques ◽  
A. B. Nascimento ◽  
V. P. Oliveira ◽  
A. R. S. Coutinho ◽  
M. E. O. A. Assumpção ◽  
...  

The present work evaluated the reversible meiosis inhibition effect on the development of swine embryos produced by in vitro fertilization (IVF) or parthenogenetic activation (PA). The efficiency of PZM3 and NCSU23 embryo culture media was also evaluated. Oocytes from ovaries collected at a slaughterhouse were subjected to IVM in two different groups: CHX (cycloheximide 5 µM for 10 h) and control, both with TCM-199 + 3.05 mM glucose + 0.91 mM sodium pyruvate + 10% porcine follicular fluid (pFF) + 0.57 mM cystein + 10 ng epidermal growth factor (EGF)/mL + 10 IU eCG/mL + 10 IU hCG/mL for the initial 22 h. In the remaining period (20 h for CHX and 22 h for control), medium without hormones was utilized. After IVM, oocytes were denuded and fertilized for 6 h (IFV) or the matured oocytes were submitted to activation by electric pulses (PA) (2 DC of 1.5 kV/cm for 30 µs), incubated for 1 h in culture medium with 10 μM of CHX, and again submitted to the same electric pulses for 60 µs. Embryo development was evaluated by cleavage rate on Day 3 and blastocyst rate and blastocyst cell number on Day 7 of culture. Cleavage and blastocyst rates were analyzed by the equality-of-two-ratios test and cell number by the Kruskal-Wallis and Mann-Whitney tests (P < 0.05). In relation to IVF, the PZM3 medium was more efficient than NCSU23 for cleavage rate in the CHX group (PZM3: 68.4%, NCSU23: 44.4%) and had a better blastocyst rate in the control group (PZM3: 13.4%, NCSU23: 5.6%). With reference to PA, NCSU23 presented better cleavage and blastocyst rates than PZM3 in the CHX group (NCSU23: 89.5%, PZM3: 78.5% and NCSU23: 20.4%, PZM3: 13.0%, respectively). In the control group, only the NCSU23 blastocyst rate was higher than that for PZM3 (NCSU23: 22.5%, PZM3: 10.8%). No culture medium effect on cell number mean of IVF and PA blastocysts was observed. Maturation block improved cleavage rates in IVF groups cultured with PZM3 (68.4% and 50.6%, respectively, for CHX and control) and in PA groups cultured with NCSU23 (89.5% and 80.3%, respectively, for CHX and control), but no improvement of blastocyst rates in both groups (IVF and PA) was verified. Table 1 below shows that maturation block decreased the IVF and increased the PA blastocyst cell numbers. As older oocytes are more effectively activated, oocytes blocked with CHX achieved the maturation stage faster than the control group, therefore resulting in high-quality PA blastocysts. In conclusion, PZM3 was more efficient for IVF embryo production in contrast to NCSU23, whereas NCSU23 can be indicated for PA embryo production. Moreover, maturation blockage with CHX influenced blastocyst cell number, decreasing in IVF embryos and increasing in PA embryos. Table 1. Mean (±SD) of blastocyst cell numbers for IVF or PA groups after in vitro maturation without (control) or with cycloheximide (CHX) and cultured in NCSU23 or PZM3 medium This work was supported by FAPESP 02/10747–1.


1996 ◽  
Vol 5 (5) ◽  
pp. 509-514 ◽  
Author(s):  
Kristiina Bredbacka ◽  
Peter Bredbacka

In this study we evaluated the use of a chemically defined medium in the production of blastocysts from bovine oocytes fertilized in vitro. As culture medium we used CRI-PVP, a modification of CRlaa medium with bovine serum albumin replaced by polyvinylpyrrolidone. After 168 h of culture (192 h after insemination) 8.7%, 10.5 and 12.8% of the cleaved embryos developed to the blastocyst stage in the presence of 0, 2 or 200 nM insulin, respectively. The supplementation of 200 nM insulin tended to increase cell numbers in morulae and blastocysts (P=0.10). It is concluded that CRI-PVP can be used as a chemically defined medium in the production of blastocysts from bovine 1-cell embryos. However, further modifications are needed, and the insulin concentrations used may be below the optimum for blastocyst production.


2008 ◽  
Vol 20 (1) ◽  
pp. 102
Author(s):  
N. Maedomari ◽  
K. Kikuchi ◽  
M. Fahrudin ◽  
N. Nakai ◽  
M. Ozawa ◽  
...  

Metaphase-II chromosome transfer (M-II transfer) of oocytes is considered to be one of the advanced procedures to improve fertilization and developmental abilities of oocytes with poor cytoplasmic maturation. The aim of this study was to investigate the developmental capacity after IVF and IVC of porcine oocytes reconstructed from karyoplasts and cytoplasts produced by centri-fusion (Fahrudin et al. 2007 Cloning Stem Cells 9, 216–228). In brief, IVM oocytes (Kikuchi et al. 2002 Biol. Reprod. 66, 1033–1041) with a visible first polar body were centrifuged at 13 000g for 9 min to stratify the cytoplasm. Then the zonae pellucidae were removed with pronase treatment. Zona-free oocytes were layered on a 300-µL discontinuous gradient of Percoll in TCM-HEPES with 5 µg mL–1 of cytochalasin B. After centrifugation at 6000g for 4 s, fragmented cytoplasms with approximately equal volumes were obtained, stained with Hoechst-33342, and classified into cytoplasm with (K; karyoplast) or without (C; cytoplast) chromosomes. One karyoplast was fused with 0, 1, 2, 3, and 4 cytoplasts (K, K + 1C, K + 2C, K + 3C, and K + 4C, respectively) by an electric stimulation with a single DC pulse (1.5 kV cm–1 for 20 µs) and cultured for 1 h. Zona-free oocytes without any reconstruction served as control oocytes. The diameters of the reconstructed and control oocytes were measured. All specimens were fertilized in vitro with frozen–thawed boar sperm, and cultured using the well of the well (WOW) system (Vajta et al. 2000 Mol. Reprod. Dev. 55, 256–264). Their fertilization status and developmental competence were examined. Data were analyzed by ANOVA followed by Duncan's multiple range tests. The diameter differed significantly among K to K + 4C oocytes (75.0–127.1 µm; P < 0.05), whereas the diameter of K + 2C oocytes was similar to that of the control oocytes (110.5 µm). Regardless of the cytoplast volume, sperm penetration rates (73.1–93.8%) for K to K + 4C oocytes were not significantly different compared to control oocytes (78.0%). Male pronuclear formation rates of K to K + 4C oocytes (92.3–97.1%) were also not different significantly different compared to control oocytes (96.6%). However, monospermy rates of K oocytes was significantly higher (61.6%; P < 0.05) than those of the reconstructed (K + 1C to K + 4C; 18.2–34.9%) and control oocytes (32.9%). The blastocyst formation rates in K, K + 1C, K + 2C, and K + 3C groups (0.0–9.8%; P < 0.05) were significantly lower than those in the control and K + 4C groups (17.8% and 15.3%, respectively; P < 0.05). The total cell numbers per blastocyst in K + 1C and K + 2C groups (7.5 and 8.3 cells, respectively) were significantly lower than in the control, K + 3C, and K + 4C groups (15.3–26.2 cells; P < 0.05). These results suggest that the cytoplast volume of porcine M-II transferred oocytes, produced by reconstruction from a karyoplast and cytoplast(s) and centri-fusion, is important for their ability to develop to the blastocyst stage and influences cell number.


2006 ◽  
Vol 18 (2) ◽  
pp. 194
Author(s):  
M. Ozawa ◽  
T. Nagai ◽  
M. Fahrudin ◽  
N. W. K. Karja ◽  
H. Kaneko ◽  
...  

Successful in vitro production of blastocysts from immature oocytes can be carried out using in vitro oocyte maturation (IVM), fertilization (IVF), and embryo culture (IVC) at a high level of repeatability in the porcine. However, the rates of in vitro development of IVM/IVF oocytes to the blastocyst stage remained around 20%. The environment in vitro is so simple and materially limited that there exist several stressors in vitro that disturb normal embryo development. Oxidative stress, which is caused by excess production of reactive oxygen species, is a major disturbing factor for the development of pre-implantation embryos in vitro. The series of present experiments were conducted using culture conditions with enhanced reducing capacity by the addition of glutathione (GSH) or thioredoxin to the culture medium to monitor developmental competence of porcine embryos and to verify their intracellular redox status. Cumulus-oocyte complexes were obtained from ovaries recovered from prepubertal gilts. Putative zygotes were produced by IVM of oocytes, followed by IVF (designated as Day 0). They were then cultured in modified NCSU-37 media containing GSH or thioredoxin as an antioxidant, or without any antioxidant (control), and blastocyst development rates on Day 6 were monitored. In addition, intracellular GSH content as a reducing parameter and intracellular H2O2 level as an oxidative parameter were measured; the intracellular redox status in the embryo was verified by the ratio of the GSH to the H2O2. Measurements in each group were replicated six times. Percentages of the embryos that developed to the blastocyst stage were significantly increased when 0.5 or 1.0 �M GSH (29.6 � 2.7% or 30.4 � 3.5%, and P < 0.05 or 0.01, respectively) or 1.0 mg/mL thioredoxin (30.6 � 2.4%, P < 0.01) was added to the medium compared to the percentage in the control group (20.1 � 2.2%). Intracellular redox status in embryos at the 8- to 12-cell stage or blastocysts was drastically reduced in GSH- or thioredoxin-added groups compared to that in the control group (P < 0.05 to 0.001). Furthermore, GSH or thioredoxin addition to the medium increased total cell numbers (48.3 � 2.1 to 49.2 � 2.1) and lowered ratios of apoptotic cells (6.2 � 0.6% to 7.0 � 0.7%) in blastocyst compared to those values in the control group (P < 0.05; cell number = 39.3 � 2.0, apoptosis rate = 11.1 � 1.1%) (37 to 53 embryos in each group were used for the TUNEL assay). These results suggest that the administration of GSH or thioredoxin to the culture medium improves in vitro embryonic development after IVM/IVF of oocytes, and that these beneficial effects are associated with maintenance of the intracellular redox status in a reduced state in porcine embryos.


2008 ◽  
Vol 20 (1) ◽  
pp. 197
Author(s):  
N. A. Wani

Identification of an optimal protocol for activation of the MII oocytes in a species like camel not only allows us to evaluate the quality of oocytes after their in vitro maturation, but also is required for the success of advanced technologies like cloning. The present study was aimed to determine activation of in vitro-matured dromedary (Camelus dromedarius) oocytes using ionomycin or ethanol followed by sequential culture in phosphorylation inhibitor (6-dimethylaminopurine) or the specific maturation promoting factor inhibitor (roscovitine). Cumulus–oocyte complexes (COCs), collected from slaughterhouse ovaries, were randomly distributed to 4-well culture plates (20–25 COCs/well) containing 500 µL of the maturation medium. The maturation 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, 20 ng mL–1 epidermal growth factor, 50 µg mL–1 gentamycin, 10 µg mL–1 bFSH, 10 µg mL–1 bLH, 1 µg mL–1 estradiol, and 10% estrous dromedary serum (EDS). The COCs were cultured at 38.5�C in an atmosphere of 5% CO2 in air for 36–40 h. The COCs were either fertilized in vitro (positive control) using epididymal spermatozoa collected from slaughtered males or activated with 5 µm ionomycin for 5 min or 7% ethanol for 7 min, both followed by exposure to 2 mm 6-DMAP or 50 µm roscovitine for 4 h. After being washed thoroughly in embryo culture medium, they were cultured for a period of 7 days at 38.5�C in an atmosphere of 5% CO2, 5% O2, and 90% N2 in air. The 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 gentamicin, 1% insulin-transferrin-selenium (ITS) media supplement, and 10% EDS. First cleavage was recorded on Day 2 and the number of embryos developing to morulas and blastocysts was recorded on Day 7 of culture. The proportions of oocytes cleaved were 58.6 � 4.4, 55.9 � 4.5, 49.1 � 5.3, 43.2 � 6.05, and 54.1 � 3.3%, while the proportions of cleaved oocytes reaching blastocyst stage were 22.5 � 0.9, 19.1 � 2.8, 9.04 � 3.3, 8.2 � 3.8, and 15.2 � 2.3%, and those at morula stage were 61.1 � 4.9, 54.6 � 6.2, 67.1 � 7.2, 57.8 � 4.6, and 53.6 � 5.6% in the ionomycin/ 6-diethylaminopurine, ionomycin/roscovitine, ethanol/6-diethylaminopurine, ethanol/roscovitine, and IVF groups, respectively. The proportions of blastocysts obtained in the ionomycin/6-diethylaminopurine and ionomycin/roscovitine groups were higher (P < 0.05) when compared with the ethanol/6-diethylaminopurine and ethanol/roscovitine groups. Also, the proportion of blastocysts obtained in the ionomycin/6-diethylaminopurine group was higher than that in the in vitro-fertilized group. In summary, methods for oocyte or cytoplast activation in dromedary camel incorporating ionomycin/6-diethylaminopurine and ionomycin/roscovitine giving better results than those incorporating ethanol/6-diethylaminopurine and ethanol/roscovitine.


2005 ◽  
Vol 17 (2) ◽  
pp. 200
Author(s):  
B. White ◽  
M. Montagner ◽  
G. Mills ◽  
P. Gonçalves ◽  
R. Christenson

Development of improved protocols for cryopreservation of zona pellucida-intact porcine embryos could greatly impact the swine industry. Our aim was to investigate in vitro development following cryopreservation of embryos from Chinese Meishan (M) and occidental white cross (WC) breeds using a modified protocol described previously (Misumi K et al. 2003 Theriogenology 60, 253–260). First-parity M sows (n = 11) and WC gilts (n = 13) were observed for estrus every 12 h and inseminated at 12 and 24 h after estrous onset within breed using semen from 2 different boars. Females were sacrificed between Days 4.5 and 6 after estrus and embryos were collected using Beltsville embryo culture medium (BECM). Compact morula (CM) or blastocyst stage embryos from each female within breed were randomly allocated either directly into the culture system to serve as controls (68 M and 48 WC embryos) or to undergo cryopreservation. A total of 101 M and 78 WC embryos were cryopreserved using the following protocol: (1) 5 min in BECM + 10% ethylene glycol (EG); (2) 5 min in BECM + 10% EG + 0.27 M sucrose + 1% polyethylene glycol (PEG); and (3) 30 to 45 s in BECM + 40% EG + 0.36 M sucrose + 2% PEG. In the last solution, 5 to 10 embryos in a 5- to 10-μL microdrop attached to a fine glass pipette were exposed to the vapor phase of liquid nitrogen (LN2) for 15 s and then plunged into LN2. The pipette tip was broken and the tip and associated frozen microdrop were placed inside an LN2-submerged 2-mL cryotube containing a hole in the lid for 1 h. Next, embryos were thawed using a 4-step (5 min each) procedure: (1) BECM + 5% EG + 0.57 M sucrose; (2) BECM + 2.5% EG + 0.29 M sucrose; (3) BECM + 0.3 M sucrose; and (4) BECM alone. All procedures were performed with solutions maintained at 37°C. Cryopreserved and control embryos were cultured in 50 μL drops of modified Whitten's medium + 1.5% BSA under oil at 37°C in a 5% CO2 in air environment and scored daily for development. For embryos undergoing cryopreservation, retrieval rates from cryovials were 92% and 96% for M and WC, respectively. The percentage of embryos surviving 24 h after cryopreservation without lysis or degeneration was higher for M (72%) than for WC (44%; P < 0.001; χ2-test). However, in vitro development of embryos that survived cryopreservation was not different between M and WC at the expanded (64%) or hatched (22%) blastocyst stages. Developmental rates were significantly higher for control embryos than for frozen embryos from both breeds. Rates of expanded blastocyst formation did not differ between M and WC control embryos (98% and 95%, respectively), but more M embryos developed to the hatched blastocyststage (22% for M v. 9% for WC; P < 0.05). Our results suggest that M embryos have a higher capacity to survive the vitrification process than WC embryos. Funding for M. Montagner was provided by CAPES, Brazil.


2004 ◽  
Vol 16 (2) ◽  
pp. 262
Author(s):  
C. Suzuki ◽  
K. Yoshioka ◽  
S. Iwamura

We previously developed an in vitro production (IVP) system for porcine embryos and obtained piglets after surgical transfer of blastocysts cultured in Porcine Zygote Medium (PZM)-4. However, the developmental competence of pig IVP embryos to the blastocyst stage is still low and further improvement of IVC medium is needed. In the present study, we evaluated the effects of the addition of glutamine (Gln), hypotaurine (HT), taurine (Tau), BME-essential (EA) and MEM-nonessential (NA) amino acids solutions to PZM-4, and the replacement of polyvinyl alcohol (PVA) with BSA on embryo development to blastocysts. Moreover, the developmental competence of IVP blastocysts after nonsurgical embryo transfer (NS-ET), using a flexible catheter (FC) for deep intrauterine insemination, was investigated. Porcine COC from prepubertal gilts were matured and fertilized in vitro, using frozen-thawed ejaculated boar semen. Presumptive zygotes were cultured in PZM-4, as a basal culture medium, until Day 5 after IVF. Data from six replicates were analyzed by ANOVA. Addition of 0.25 to 4mM Gln to PZM-4 (containing 5mM HT) significantly increased the percentage of embryos that developed to blastocysts (15 to 31%), with addition of 2mM Gln significantly increasing the total cell numbers in blastocysts (43±17 cells) compared with no addition (3% and 20±4 cells, respectively). Addition of 1.25 to 10mM HT to HT-free PZM-4 supplemented with 2mM Gln (named PZM-5) significantly increased the percentage of embryos that developed to blastocysts (22 to 28%) compared with control (no HT;; 4%). In the culture with HT-free PZM-5, addition of 5mM Tau significantly increased blastocyst yield (17%) compared with control (4%). However, Tau addition in the presence of 5mM HT had no effect on development to the blastocyst stage. In combinations of EA and NA added to PZM-5, a single dose of EA significantly increased the percentage of embryos that developed to blastocysts (27%) compared with no dose (19%) or with a double dose of EA (20%), while a double dose of NA significantly increased the total cell numbers in blastocysts (43±16 cells) compared with no NA (37± 6 cells). Replacement of PVA with BSA in PZM-5 had no effect on embryo development to the blastocyst stage. Crossbred sows were used as recipients for NS-ET, and had their estrous cycle synchronized by a described previously method (Yoshioka et al., 2002 Biol. Reprod. 66, 112–119). Five days after hCG injection, a FC was introduced via the cervix into the uterine horn of recipients without sedation. Day-5 blastocysts cultured in PZM-5 were then transferred together with 5ml of TALP-Hepes (45 to 50 blastocysts/recipient). Of 6 recipients, one sow became pregnant and farrowed 7 piglets. Our results indicate that the addition of amino acids to PZM-4 can improve porcine embryo development to the blastocyst stage, and that blastocysts cultured in a chemically defined medium, PZM-5, can develop to full-term following NS-ET.


2010 ◽  
Vol 22 (1) ◽  
pp. 235
Author(s):  
T. Somfai ◽  
Y. Inaba ◽  
Y. Aikawa ◽  
M. Ohtake ◽  
S. Kobayashi ◽  
...  

Polydimethylsiloxane (PDMS) is a non-toxic silicon compound. Its excellent optical characteristics and easy preparation make it a good candidate material for the molding of custom-shaped dishes for embryo culture. We investigated the feasibility of PDMS-based well of the well (WOW) dishes for in vitro culture of bovine embryos under different oxygen tensions. The WOW dishes with 25 micro-wells (each of 175 μm depth and 250 μm width in diameter arranged in 5 columns and 5 rows) were molded from PDMS prepared either under atmospheric (Experiment 1) or reduced (0.1 MPa) (Experiment 2) air pressure to remove air bubbles. Presumptive zygotes obtained by the in vitro maturation and fertilization of follicular oocytes were placed and cultured for 7 days in traditional micro-drops of culture medium (Control) or in the micro-wells of PDMS-based WOW dishes (PDMS-WOW), both covered by paraffin oil. The culture medium was CR1aa supplemented with 5% calf serum. The culture drop size was 125 μL (5 μL/oocyte) in both groups. Embryo development and blastocyst cell numbers between Control and PDMS-WOW groups were compared either under 20% or 5% O2 tensions. There was no statistical difference in cleavage and blastocyst rates (ranging between 82.3-86.4% and 34.0-45.8%, respectively) between Control and PDMS-WOW embryos irrespective of oxygen tension and dish production method. In Experiment 1, the mean total cell numbers in blastocysts were lower in the PDMS-WOW group than that in Control under 20% O2 (105.0 ± 5.5 and 130.4 ± 9.9, respectively) (P < 0.05, ANOVA); however, the application of 5% O2 significantly improved the cell numbers and eliminated the difference between the PDMS-WOW and Control groups (135.4 ± 6.2 and 148.0 ± 9.0, respectively). In Experiment 2, there was no significant difference in mean total cell numbers in blastocysts between the PDMS-WOW and Control either under 20% O2 (97.2 ± 5.7 and 103.9 ± 8.9, respectively) or 5% O2 (147.5 ± 12.1 and 157.3 ± 3.9, respectively). The numbers and rates of inner cell mass and trophectoderm cells did not differ between the Control and PDMS-WOW groups, irrespective of O2 tension and production method. Our results demonstrate that bovine embryos can develop to the blastocyst stage in PDMS-based WOW dishes; however, it may express detrimental effects on embryonic cell numbers, which can be neutralized by the application of low O2 tension during culture or reduced air pressure during the PDMS preparation. This work was supported by the Research and Development Program for New Bio-Industry Initiatives.


Zygote ◽  
2003 ◽  
Vol 11 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Y.H. Choi ◽  
Y.G. Chung ◽  
S.C. Walker ◽  
Westhusin M.E. ◽  
K. Hinrichs

This study was conducted to evaluate the effects of insulin-like growth factor I (IGF-I) and other media factors during oocyte maturation, and the presence of different compositions of amino acids in embryo culture medium, on the development of equine embryos. Oocytes recovered from slaughterhouse-derived ovaries were matured in vitro for 24 h and those with a polar body were subjected to intracytoplasmic sperm injection (ICSI) or nuclear transfer with adult fibroblasts (NT). For ICSI embryos, there were no significant differences in rates of morphological cleavage, cleavage with normal nuclei or average nucleus number at 96 h post-ICSI between the absence and presence of IGF-I in maturation medium, or between embryos cultured in G1.2 or a modified CZB medium (CZB-C). Embryos produced by interspecies NT (equine donor cells into bovine cytoplasts) also showed no difference in cleavage rate or average nucleus number whether cultured in G1.2 or in CZB-C. The rates of cleavage, cleavage with normal nuclei and average nucleus number of equine NT embryos were not significantly different among oocytes matured in M199 with FSH in the presence or absence of IGF-I, or in EMMI medium, which contains IGF-I, epidermal growth factor, steroid hormones, FSH and LH. There were no differences in development of equine NT embryos cultured in any of three amino acid treatments (with or without non-essential amino acids, or containing taurine, hypotaurine and cysteine only). The cleavage rate and average nucleus number of parthenogenetically activated oocytes (treated similarly to NT oocytes but not enucleated or subjected to donor cell injection) were significantly (p < 0.05) higher than those for NT embryos. These results indicate that the presence of IGF-I or of EMMI medium during in vitro maturation of equine oocytes does not have a beneficial effect on their developmental competence as assessed at 96 h. Presence or absence of non-essential amino acids in embryo culture medium does not affect development of NT embryos within the first 96 h of culture. Factors associated with enucleation or nuclear transfer decrease the developmental competence of equine NT embryos. CZB-C medium may be used for culture of equine embryos with results similar to those obtained with G1.2 medium, thus providing a base medium that may be modified for further study of culture requirements of equine embryos.


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