44 IN VITRO DEVELOPMENT OF INTERSPECIES NUCLEAR TRANSFER EMBRYOS GENERATED WITH BOVINE OOCYTES AND EQUINE SKIN FIBROBLASTS

2011 ◽  
Vol 23 (1) ◽  
pp. 128
Author(s):  
J. Lee ◽  
J. Park ◽  
Y. Chun ◽  
W. Lee ◽  
K. Song
Keyword(s):  
Nuclear Transfer ◽  
Polar Body ◽  
Donor Cell ◽  
Skin Fibroblasts ◽  
Developmental Competence ◽  
Cleavage Rate ◽  
Cell Stage ◽  
Bovine Oocytes

Study for equine somatic cell nuclear transfer (SCNT) is an attractive field for research, but it has not been a major field of study because it is hard to obtain a sufficient number of ovaries and it takes a lot of time and effort for the recovery of oocytes matured in vivo by ovum pickup. It was reported that the bovine cytoplast could support the remodelling of equine donor cells (Zhou et al. 2007 Reprod. Domest. Anim. 42, 243–247). The objectives of this study are 1) to monitor the early events of equine SCNT by interspecies SCNT (isSCNT) between bovine cytoplast and equine donor cell, and 2) to investigate the developmental competence of isSCNT embryos. Bovine oocytes were recovered from the follicles of slaughtered ovaries, and matured in TCM-199 supplemented with 10 mU mL–1 FSH, 50 ng mL–1 EGF, and 10% FBS at 39°C under 5% CO2 in air for 22 h. Fibroblasts derived from bovine or equine skin tissues were synchronized at G0/G1 stage by contact inhibition for 72 h. After IVM, oocytes with polar body were enucleated and electrically fused with equine or bovine skin fibroblasts (1.0 kV cm–1, 20 μs, 2 pulses). Fused couplets were activated with 5 μM ionomycin for 4 min followed by 5 h culture in 10 μg mL–1 cycloheximide (CHX) and/or 2 mM 6-DMAP, and cultured in modified synthetic oviduct fluid (mSOF) at 39°C under 5% CO2, 5% O2, and 90% N2 for 7 days. All analyses were performed using SAS (version 9.1; SAS Institute, Cary, NC, USA). The cleavage rate of isSCNT embryos derived from equine cell was not different (252/323, 78.7%; P = 0.94) from that of SCNT embryos derived from bovine cell (230/297, 79.2%). However, the rate of isSCNT embryos developed to over 8-cell stage was lower (3.3%; P < 0.0001) than that of bovine SCNT embryos (39.4%), and total cell number of isSCNT embryos developed to over 8-cell stage was lower (17.5, n = 12; P < 0.0001) than that (80.8, n = 110) of bovine SCNT embryos. Also, the rate of blastocyst formation of isSCNT embryos (0/323; 0.0%) was lower (P < 0.0001) than that of bovine SCNT embryos (83/297; 29.3%). Meanwhile, reconstructed oocytes for isSCNT were fixed at 8 h after activation to investigate the formation of pseudo-pronucleus (PPN) after post-activation treatment with CHX or CHX+6-DMAP. The ratio of oocytes with single PPN after treatment with CHX+6-DMAP (26/35; 74.3%) was not different (P = 0.63) from that of oocytes treated with CHX (24/36; 68.1%). Although isSCNT embryos derived from bovine cytoplast and equine donor cell could not develop to more than the 16-cell stage, it is believed that the results of this isSCNT study could be used for the preliminary data regarding the reprogramming of donor cell in equine SCNT.

scholarly journals Developmental competence in vivo and in vitro of in vitro-matured equine oocytes fertilized by intracytoplasmic sperm injection with fresh or frozen-thawed spermatozoa

Reproduction ◽  
2002 ◽  
pp. 455-465 ◽  
Author(s):  
YH Choi ◽  
CC Love ◽  
LB Love ◽  
DD Varner ◽  
S Brinsko ◽  
...  
Keyword(s):  
Intracytoplasmic Sperm Injection ◽  
Polar Body ◽  
Cumulus Cells ◽  
Fertilization Rate ◽  
Developmental Competence ◽  
Cleavage Rate ◽  
First Polar Body ◽  
Bovine Oocytes

This study was undertaken to evaluate the development of equine oocytes in vitro and in vivo after intracytoplasmic sperm injection (ICSI) with either fresh or frozen-thawed spermatozoa, without the use of additional activation treatments. Oocytes were collected from ovaries obtained from an abattoir and oocytes classified as having expanded cumulus cells were matured in M199 with 10% fetal bovine serum and 5 microU FSH ml(-1). After 24-26 h of in vitro maturation, oocytes with a first polar body were selected for manipulation. Fresh ejaculated stallion spermatozoa were used for the experiment after swim-up for 20 min in sperm-Tyrode's albumen lactate pyruvate. Frozen-thawed spermatozoa from the same stallion were treated in a similar way. Spermatozoa were immobilized and injected into the oocytes using a Piezo drill. Presumptive zygotes were cultured in G1.2 medium for 20 or 96 h after the injection was administered, or were transferred to the oviducts of recipient mares and recovered 96 h later. In addition, bovine oocytes with first polar bodies were injected with the two types of stallion spermatozoa and fixed 20 h after injection to examine pronuclear formation. Fertilization rate (pronucleus formation and cleavage) at 20 h after injection of spermatozoa was not significantly different between fresh and frozen-thawed sperm groups in either equine or bovine oocytes. Pronucleus formation after injection of spermatozoa into bovine oocytes was significantly higher than that for equine oocytes (P < 0.05). There were no significant differences in cleavage rate or average number of nuclei at 96 h between equine oocytes injected with fresh or frozen-thawed spermatozoa. However, embryos developed in vivo for 96 h had a significantly higher number of nuclei in both sperm treatments compared with those cultured in vitro. These results indicate that good activation rates may be obtained after injection of either fresh or frozen-thawed equine spermatozoa without additional activation treatment. Injection of frozen-thawed equine spermatozoa results in similar embryo development to that obtained with fresh equine spermatozoa. In vitro culture of equine zygotes in G1.2 medium results in a similar cleavage rate but reduced number of cells compared with in vivo culture within the oviduct. Bovine oocytes may be useful as models for assessing sperm function in horses.

scholarly journals 196 IN VITRO DEVELOPMENT OF RECONSTRUCTED WATER BUFFALO (BUBALUS BUBALIS) OOCYTES AFTER FETAL SKIN FIBROBLAST CELL NUCLEAR TRANSFER

2005 ◽  
Vol 17 (2) ◽  
pp. 248
Author(s):  
C.R. Meena ◽  
S.K. Das
Keyword(s):  
Nuclear Transfer ◽  
Cytochalasin B ◽  
Polar Body ◽  
Fibroblast Cell ◽  
Skin Fibroblasts ◽  
Developmental Competence ◽  
Fetal Skin ◽  
Cell Stage ◽  
First Polar Body

The present study was undertaken to explore the feasibility of using buffalo fetal skin fibroblasts as donor nuclei and to determine the developmental competence of embryos following transfer of these nuclei to in vitro-matured enucleated buffalo oocytes. Skin cells were isolated from 1–2-month-old fetuses, obtained from an abattoir, by enzymatic digestion (0.5% w/v trypsin + 0.05% w/v collagenase in Dulbecco's PBS) for 15–20 min. The cells were washed four times with Dulbecco's PBS and then once with RPMI-1640 medium + 10% FBS by centrifugation at 600g. The cells were then cultured in the same medium in a CO2 incubator (5% CO2 in air) at 38.5°C for 2–3 days. COCs collected from slaughterhouse buffalo ovaries were subjected to IVM in the IVM medium (TCM-199 + 1 μg mL−1 E-β + 5 μg mL−1 FSH-P + 10 μg mL−1 LH + 10% FBS) for 22–24 h in a CO2 incubator (5% CO2 in air) at 38.5°C. Oocytes were denuded with 0.1% trypsin followed by repeated pipetting and then enucleated by aspirating the first polar body and 10–15% of nearby cytoplasm with a micromanipulator. Two different types of donor cells (growing cells and those arrested with cytochalasin-B) were used for reconstruction of oocytes. The reconstructs were electrofused and incubated in the activation medium (TCM-199 + 8 μg mL−1 cytochalasin-B + 10% FBS) for 4 h. These were then cultured in IVC medium (TCM-199 + 10% FBS) in a CO2 incubator (5% CO2 in air) at 38.5°C for 48 h. Next, the cleaved embryos were co-cultured with buffalo oviductal cells in embryo development medium. Out of 119 denuded matured oocytes which were enucleated and reconstructed with growing cells, 78 (65.5%) were electrofused, activated and cultured, out of which 4 (5.1%) reconstructs cleaved and developed to the 2-cell stage, 3 (3.8%) reached the 4-cell stage, and 1 (1.3%) reached the 8-cell stage. In the synchronized group, out of 100 denuded matured oocytes which were reconstructed with cytochalasin-B blocked cells, 40 (40%) were electrofused, activated, and cultured, out of which 4 (10%) developed to the 2-cell stage, 3 (7.5%) to the 4-cell stage, 2 (5.0%) to early morula stage, and 1 (2.5%) to blastocyst stage. These results suggest that buffalo fetal skin fibroblasts could be used as donor nuclei for the production of buffalo embryos after nuclear transfer to enucleated in vitro-matured buffalo oocytes.

Development in vitro and in vivo of aggregated parthenogenetic bovine embryos

1995 ◽  
Vol 7 (5) ◽  
pp. 1073 ◽  
Author(s):  
A Boediono ◽  
S Saha ◽  
C Sumantri ◽  
T Suzuki
Keyword(s):  
Cytochalasin B ◽  
Polar Body ◽  
Cleavage Rate ◽  
Development In Vitro ◽  
Second Polar Body ◽  
Bovine Oocytes ◽  
Longitudinal Diameter ◽  
Parthenogenetic Embryos

Mature bovine oocytes were activated with 7% ethanol followed by cytochalasin B or D treatment. Most oocytes extruded a second polar body and formed one pronucleus when treated with 7% ethanol alone [35/43 (81%)]. With ethanol followed by cytochalasin B or D, overall activation frequency was 70% (309/441), with activated oocytes containing two pronuclei. The cleavage rate was not significantly different between treatment with ethanol alone and ethanol followed by 5 micrograms mL-1 cytochalasin B, but it was significantly lower than in fertilized oocytes (P < 0.01). However, the blastocyst production rate was significantly different (P < 0.01) among the treatments. The incidence of parthenogenetic embryos with normal (diploid) complements and with chromosome anomalies (2N/4N) was 68% (17/25) and 32% (8/25) respectively, and this was not affected by cryopreservation treatment. The longitudinal diameter of aggregated-four embryos cultured in vitro was greater (P < 0.01) than aggregated-two or single embryos. One of the aggregated-four parthenogenetic embryos was further cultured in vitro and developed up to Day 27 after activation, with a diameter of 2980 microns. The aggregated-four parthenogenetic embryos were transferred to five recipients. The oestrus was prolonged in three recipients and they returned to oestrus on Day 57, 62 and 67 after the previous oestrus. These results indicate that aggregating parthenogenetic embryos can prolong their survival in vitro and in vivo.

359 ICSI AND ACTIVATION OF OOCYTES RECOVERED FROM TRANSITIONAL AND CYCLING MARES

2006 ◽  
Vol 18 (2) ◽  
pp. 286 ◽  
Author(s):  
T. Suh ◽  
S. Purcell ◽  
G. Seidel Jr
Keyword(s):  
Growth Factor ◽  
Polar Body ◽  
Follicular Development ◽  
Transitional Period ◽  
Developmental Competence ◽  
Blastocyst Development ◽  
Cleavage Rate ◽  
First Polar Body

Ovarian follicular development in mares during the transitional period before the breeding season leads to an accumulation of antral follicles of various sizes. The quality of oocytes at this stage may be compromized until the first seasonal ovulation. In this study, we evaluated the developmental competence of oocytes recovered from transitional and cyclic mares, and the effect of zygote activation after intracytoplasmic sperm injection (ICSI). A 2 × 2 × 2 factorial experiment consisting of oocytes from transitional and cyclic mares, two follicle sizes (10 to 20 and 20+ mm), and two treatments (control and activated) was conducted. Follicular oocytes of 14 mares were aspirated in March and April (transitional) and May to July (cyclic) five times per each period at 10-day intervals, without use of hCG. Oocytes aspirated from mares were matured in vitro in a defined medium similar to SOF plus FSH, LH, epidermal growth factor (EGF), insulin-like growth factor (IGF), estradiol (E2), prostaglandin (P4) and 10% FCS, for 30 ± 1 h under 5% CO2 in air at 38.5°C; oocytes with a first polar body were used for ICSI. Motile sperm from frozen-thawed semen were used for sperm injection with a piezo-driven pipet. For activation after ICSI, presumptive zygotes were cultured in G1.3 containing 0.02 µM phorbol 12-myristate 13-acetate (PMA) for 2 h, and then in 2 mM 6-dimethylaminopurine (6-DMAP) for 3 h under 6% CO2 in air at 38.5°C. Zygotes were cultured in 50 µL drops of DMEM/F12 containing 10% FCS for 9 days at 38.5°C in 5% CO2/5% O2/90% N2. Medium was replaced every 3 days. Cleavage and blastocyst rates were calculated based on non-degenerating injected oocytes. Data were analyzed by Fisher's exact test. A total of 115 and 78 oocytes were recovered from cyclic and transitional mares. Average maturation rates to MII in the respective groups were 76.5 and 65.4%, respectively (P < 0.07), and those of 10 to 20 and 20+ mm follicle groups were 70.6 and 80.0%, respectively (P > 0.05). The average cleavage rate in cyclic mares was higher than in transitional mares, and that of the activated group averaged over follicle sizes was higher than that of controls (P < 0.05; Table 1); those of 10 to 20 and 20+ mm follicle groups were not different (P < 0.05; Table 1). Blastocyst rates per oocyte within main effects were not different (P < 0.05; Table 1). Oocytes from transitional mares had lower cleavage rates than those of cyclic mares, but blastocyst development was similar. Activation of zygotes clearly improved cleavage rates of in vivo-derived immature equine oocytes after ICSI. Table 1. Main effect means of responses after ICSI

36 DEVELOPMENTAL COMPETENCE OF HUMAN AGED OOCYTES AS HOST CELLS FOR NUCLEAR TRANSFER

2006 ◽  
Vol 18 (2) ◽  
pp. 126
Author(s):  
V. Hall ◽  
D. Compton ◽  
P. Stojkovic ◽  
M. Nesbitt ◽  
M. Herbert ◽  
...  
Keyword(s):  
Nuclear Transfer ◽  
Calcium Ionophore ◽  
Developmental Competence ◽  
Host Cells ◽  
Cell Stage ◽  
Double Labeling ◽  
Immunocytochemical Analysis ◽  
Parthenogenetic Activation

The use of aged metaphase II oocytes (cultured in vitro for more than 14 h) for somatic cell nuclear transfer (SCNT) in varying species has resulted in lower developmental outcomes compared with non-aged in vitro- or in vivo-matured oocytes. However, due to limited resources of fresh oocytes for the derivation of nuclear transfer stem cell lines, further investigation in using spare oocytes is required. Aged spare oocytes (48 h post oocyte retrieval) were consigned for research (under HFEA and local ethics approval) by couples undergoing either in vitro fertilization (failed IVF oocytes, f-IVF) or intracytoplasmic sperm injection (failed-ICSI oocytes, f-ICSI) treatments. Aged oocytes were randomly assigned for double-labeling immunocytochemical analysis (f-IVF, n = 10; f-ICSI, n = 7) for the microtubule markers, NuMA and �-tubulin, or parthenogenetic activation. Immunocytochemical analysis was performed as previously described (Chatzimeletiou et al. 2005 Hum. Reprod. 20, 672-682) using primary anti-rabbit NuMA (gift from D. Compton, Dartmouth Medical School, Hanover, NH, USA) and anti-mouse DM1-�. Secondary antibodies were donkey anti-rabbit and anti-mouse immunoglobulins. Oocytes were counterstained with Hoechst 33342. Negative controls were performed as above with blocking solution substituting for primary antibodies. Parthenogenetic activation was performed for 4 h using 10 �M calcium ionophore (5 min) and 2 mM 6-dimethylaminopurine (Ca-I/DMAP) for f-IVF (n = 10) and f-ICSI oocytes (n = 11) or 10 �g/mL puromycin (Ca-I/Pur) for f-IVF (n = 12) and f-ICSI oocytes (n = 10) (4 h). Activated oocytes were cultured in a biphasic system, G1.3" and G2.3" (Vitrolife UK, Ltd., Ediburgh, Lothian, UK) for 5 days at 37 �C in 5% CO2 in humidified air. NuMA was localized to the metaphase spindle in 6/10 (60%) and 7/7 (100%) oocytes for f-IVF and f-ICSI, respectively, and/or in cytoplasmic cytasters. One f-IVF oocyte and four f-ICSI oocytes had visible tetrapolar spindles. Unusual patterns of diffuse NuMA staining containing dense foci within these regions, but not associated with the cytasters or metaphase spindle, were also observed in two f-IVF oocytes. The majority of oocytes displayed ring-like staining of DM1-�, which was aberrant in two f-ICSI oocytes. Parthenogenetic development was poor for both treatments. Cleavage rates were 17% and 20% for f-IVF using Ca-I/PUR and Ca-I/DMAP, respectively, and 40% and 45% for f-ICSI using Ca-I/PUR and Ca-I/DMAP, respectively. Fragmentation rates were high across all treatments. No parthenogenetic embryos developed beyond the 6-cell stage. Thus, the use of aged human oocytes for SCNT may be difficult due to their incapacity to artificially activate using current activation protocols and, in addition, due to the microtubule abnormalities observed in many of these aged oocytes.

IGF-I slightly improves nuclear maturation and cleavage rate of bovine oocytes exposed to acute heat shock in vitro

Zygote ◽  
2014 ◽  
Vol 23 (4) ◽  
pp. 514-524 ◽  
Author(s):  
Qi Meiyu ◽  
Di Liu ◽  
Zvi Roth
Keyword(s):  
Growth Factor ◽  
Heat Shock ◽  
Developmental Competence ◽  
Cortical Granule ◽  
Cleavage Rate ◽  
Cell Stage ◽  
Nuclear Maturation ◽  
Igf I ◽  
Bovine Oocytes

SummaryAn in vitro model of embryo production was used to examine the effects of insulin-like growth factor (IGF)-I on maturation and developmental competence of oocytes exposed to heat shock. Cumulus–oocyte complexes were matured at 38.5°C or exposed to acute heat shock (HS; 41.5°C), with or without 100 ng/ml IGF-I, for 22 h through in vitro maturation. The experimental groups were control (C), C + IGF-I, HS, and HS + IGF-I. Oocytes were fertilized at the end of maturation, and the proportion of cleaved embryos was recorded 44 h later. HS during maturation increased the proportion of TUNEL-positive oocytes (P < 0.05). HS did not have any effect on cortical granule translocation but impaired resumption of meiosis, expressed as a decreased proportion of oocytes with nuclei in metaphase I (P < 0.05) and metaphase II (MII; P < 0.05). HS decreased the proportion of oocytes that cleaved (P < 0.05), in particular those oocytes that further developed to 4-cell-stage embryos (P < 0.05). IGF-I alleviated, to some extent, the deleterious effects of HS on the oocytes as reflected by a reduced proportion of TUNEL-positive oocytes (P < 0.03). While not significant, IGF-I tended to increase the proportion of MII-stage oocytes (P < 0.08) and 4-cell-stage cleaved embryos (P < 0.06). Further examination is required to explore whether IGF-I also affects the developmental competence of oocytes exposed to HS.

scholarly journals 64COMPARISON OF DEVELOPMENTAL POTENTIAL OF IN VIVO AND IN VITRO RECIPIENT OOCYTES AFTER NUCLEAR TRANSFER IN GOAT

2004 ◽  
Vol 16 (2) ◽  
pp. 154
Author(s):  
H.S. Park ◽  
M.Y. Lee ◽  
S.P. Hong ◽  
J.I. Jin ◽  
J.K. Park ◽  
...  
Keyword(s):  
Nuclear Transfer ◽  
Electric Pulse ◽  
Serum Starvation ◽  
Cleavage Rate ◽  
Developmental Potential ◽  
In Vitro Development ◽  
Significant Difference ◽  
Vitro Development

Recent techniques in somatic cell nuclear transfer (SCNT) have been widely used for animal research. In addition, SCNT techniques may allow for the rescue of endangered species. Despite efforts for wildlife preservation, however, some threatened or endangered wild animal species will likely become extinct. As a preliminary experiment of a series in wildlife research, we tried to identify an improved method for the production of more transferable NT embryos in goats. Mature donor animals of Korean native goats (20–25kg) were synchronized with a CIDR (type G; InterAg, New Zealand) vaginal implant for 10 days followed by a total of 8 twice daily injections of 70mg of FSH (Folltropine, London, Ontario, Canada) and 400IU of hCG (Chorulon, Intervet, Moxmeer, The Netherlands). Oocytes were then collected surgically by retograde oviduct flush or direct aspiration from ovarian follicles in vivo at 29–34h after hCG. Oocytes collected from follicles were matured in TCM-199 containing 10% FBS and hormones. Prepared ear skin cells from the goat were cultured in TCM-199 containing 10% FBS at 39°C, 5% CO2 in air, and confluent monolayers were obtained. Oocytes were enucleated and donor cells from serum starvation (0.5%) culture were fused through a single electric pulse (DC 2.36kvcm−1, 17μs), and then activated by a single electric pulse (AC 5vmm−1, 5s+DC 1.56kvcm−1, 30μs) or chemical treatment (5μgmL−1 ionomycin 5min−1, 1.9mM 6-DMAP/4h). Reconstructed oocytes were cultured in M16 medium with 10% goat serum (GS) for 6–7 days. Data were analyzed by chi-square test. In in vitro development, significantly (P&lt;0.05) more oocytes were cleaved (24/30, 80.0%) and developed (7/24, 29.2%) to morula or blastocyst stage, respectively, in NT oocytes activated by Iono + DMAP compared to electric stimulated oocytes (2/21, 40.0%; 0/2, 0%). There was a significant difference in in vitro development of NT embryos by the method of oocyte collection. Cleavage rate was higher (P&lt;0.05) in NT embryos from in vivo oocytes (23/28, 82.1%) than in in vitro matured oocytes (19/35, 54.3%), and further development to morula or blastocyst was also significantly (P&lt;0.05%) higher in NT embryos from in vivo oocytes (7/23, 30.4%) than in NT embryos from in vitro matured oocytes (0/19, 0%). When we compared NT embryos to parthenotes, developmental rate was not significantly different between NT embryos and parthenotes. These results strongly suggest that the in vivo oocytes will have superior developmental potential to oocytes matured in vitro. Table 1 Effect of different oocyte source on in vitro development following caprine SCNT

scholarly journals Comparative analysis of different nuclear transfer techniques to prevent the transmission of mitochondrial DNA variants

2019 ◽  
Author(s):  
M Tang ◽  
R R Guggilla ◽  
Y Gansemans ◽  
M Van der Jeught ◽  
A Boel ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Disease Transmission ◽  
Nuclear Transfer ◽  
Smooth Endoplasmic Reticulum ◽  
Scientific Evidence ◽  
Polar Body ◽  
Comparable Rate ◽  
Carry Over

Abstract Prevention of mitochondrial DNA (mtDNA) diseases may currently be possible using germline nuclear transfer (NT). However, scientific evidence to compare efficiency of different NT techniques to overcome mtDNA diseases is lacking. Here, we performed four types of NT, including first or second polar body transfer (PB1/2T), maternal spindle transfer (ST) and pronuclear transfer (PNT), using NZB/OlaHsd and B6D2F1 mouse models. Embryo development was assessed following NT and mtDNA carry-over levels were measured by next generation sequencing (NGS). Moreover, we explored two novel protocols (PB2T-a and PB2T-b) to optimize PB2T using mouse and human oocytes. Chromosomal profiles of NT-generated blastocysts were evaluated using NGS. In mouse, our findings reveal that only PB2T-b successfully leads to blastocysts. There were comparable blastocyst rates amongst PB1T, PB2T-b, ST and PNT embryos. Furthermore, PB1T and PB2T-b had lower mtDNA carry-over levels than ST and PNT. After extrapolation of novel PB2T-b to human in vitro matured (IVM) oocytes and in vivo matured oocytes with smooth endoplasmic reticulum aggregates (SERa) oocytes, the reconstituted embryos successfully developed to blastocysts at a comparable rate to ICSI controls. PB2T-b embryos generated from IVM oocytes showed a similar euploidy rate to ICSI controls. Nevertheless, our mouse model with non-mutated mtDNAs is different from a mixture of pathogenic and non-pathogenic mtDNAs in a human scenario. Novel PB2T-b requires further optimization to improve blastocyst rates in human. Although more work is required to elucidate efficiency and safety of NT, our study suggests that PBT may have the potential to prevent mtDNA disease transmission.

41 STUDY ON THE ESTABLISHMENT OF SOMATIC CELL NUCLEAR TRANSFER USING IN VIVO-MATURED OOCYTES IN DOGS

2006 ◽  
Vol 18 (2) ◽  
pp. 129 ◽  
Author(s):  
G. Jang ◽  
M. Kim ◽  
H. J. Oh ◽  
F. Y. Heru ◽  
M. S. Hossein ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Chemical Activation ◽  
Developmental Competence ◽  
Perivitelline Space ◽  
Parthenogenetic Activation ◽  
Vaginal Cytology

The present study was performed to collect in vivo matured canine oocytes for somatic cell nuclear transfer (SCNT) and to investigate the developmental competence of canine parthenogenetic and SCNT embryos as the preliminary research for producing cloned dog. The day of ovulation as described by Hase et al. (2000 J. Vet. Med. Sci. 62, 243-248) was determined by serum progesterone levels and at that time vaginal cytology was performed to assess the cornified index. In vivo-matured oocytes were recovered by retrograde flushing of the oviducts at around 48 h (n = 20) or 72 h (n = 25) after the estimated time of ovulation. Overall size of each oocyte, as well as ooplasmic diameter, zona pellucida thickness, and perivitelline space width, was determined after removing the cumulus cells by pipetting (Exp. 1). To determine activation protocols, two treatments, (1) chemical activation (10 �M Ca ionophore for 4 min, followed by incubation for 4 h with 1.9 mM 6-dimethylaminopurine) and (2) electrical stimulation (3.1?3.4 kV/cm in 0.25M mannitol solution), were evaluated to induce parthenogenetic activation of oocytes (Exp. 2). Donor cells were obtained from the primary cell culture of a canine ear skin biopsy, and SCNT was performed according to our laboratory procedures (Jang et al. 2004 Theriogenology 62, 512-521). Three voltages (1.7?2.0 kV/cm, 2.1-2.4 kV/cm, and 3.1-3.4 kV/cm) were tested for fusion. The fused couplets were subjected to chemical or electrical stimulation as in parthenogenetic activation and in vitro developmental competence was monitored (Exp. 3). As a result, more in vivo-matured canine oocytes were obtained at 72 h (92%) than at 48 h (15%) after ovulation; the 72-h occytes had progesterone concentrations of 4-8 ng/mL and a cornified index (vaginal cytology) of 83.34. The average number of oocytes recovered was 12 and sizes of ooplasmic diameter, cytoplasm, zona pellucida, and perivitelline space in in vivo canine-matured oocytes (n = 120) were 178.8 � 9.3 �m, 125.0 � 8.2 �m, 21.7 � 3.7 �m, and 12.7 � 3.5 �m, respectively. Parthenogenetically activated oocytes developed to the 16-cell and morula stages, but failed to develop to the blastocyst stage. Among the three voltages, in the highest voltage (75.2%) the number of fused couplets was increased compared to either of the other voltages (33.3% and 44.0%). Cleavage rates (60.9% vs. 58.0%) of cloned embryos were not significantly affected by method of activation. In terms of in vitro developmental competence, cloned embryos developed to the 16-cell or morula stage in vitro after electrical or chemical activation, respectively. In conclusion, in the present study we demonstrated that measurement of progesterone levels, in combination with evaluation of vaginal cytology, can be used to determine the estimated time of ovulation in bitches. In addition, we determined fusion/activation protocols that resulted in in vitro development of a portion of parthenogenetically activated and cloned embryos to the 16-cell and morula stages. This study was supported by grants from the Biogreen 21-1000520030100000.

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