Development of four-cell hamster embryos to the blastocyst stage in vitro and its regulation by components of the culture milieu

1990 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
H Monis ◽  
BD Bavister
Keyword(s):  
Amino Acids ◽  
Co2 Concentration ◽  
Inhibitory Effect ◽  
Defined Medium ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Blastocyst Development ◽  
Cell Stage ◽  
Stage Of Development

Constituents of the culture milieu known to influence development of hamster 2-cell and 8-cell embryos were examined for effects on the 4-cell stage. Embryos were collected at the mid 4-cell stage (approx. 45-46 h after egg activation) from superovulated females and cultured for 24 h in a chemically defined medium (TLP-PVA). As with the 2-cell stage, inorganic phosphate (Pi) strongly inhibited development of 4-cell embryos, although some (14%) were able to reach the 8-cell stage or further in the presence of Pi. However, unlike 2-cell embryos, no significant inhibitory effect of glucose on development of 4-cell embryos was found. In the absence of glucose and Pi, development of 4-cell embryos was sensitive to amino acids in the medium: the mean cell number was increased using 21 amino acids compared with 4 amino acids, similarly to the 2-cell stage; however, late blastocyst development (blastocele formation) from 4-cell embryos was reduced using 21 compared with 4 amino acids, as with 8-cell embryos. Similarly to the 2-cell and 8-cell stages, raising the CO2 concentration from 5% to 10% in the gas atmosphere for culture increased the percentage of total blastocysts developing from the 4-cell stage, but did not affect the proportions of late-stage blastocysts. These data show that 4-cell-stage hamster embryos are somewhat similar to 2-cell embryos with respect to the regulation of development by constituents of the culture milieu, but, to some extent, the 4-cell embryo is a transitional stage of development.

156 OVIDUCTAL FLUID SUPPLEMENTATION DURING MATURATION AND FERTILIZATION IMPROVES IN VITRO EMBRYONIC DEVELOPMENT IN PIGS

2017 ◽  
Vol 29 (1) ◽  
pp. 187
Author(s):  
A. Goldacker ◽  
E. Winn ◽  
J. Z. Current ◽  
B. D. Whitaker
Keyword(s):  
Embryonic Development ◽  
Developmental Stages ◽  
Blastocyst Stage ◽  
Success Rates ◽  
Blastocyst Development ◽  
Cell Stage ◽  
Stage Of Development ◽  
Fluid Supplementation ◽  
Chi Square Analysis

Oviducal fluid has a major role in the maturation of gametes and the process of fertilization. The objective of this study was to determine the effects of oviducal fluid supplementation in vitro, during oocyte maturation and IVF on fertilization characteristics and early embryonic development rates. Oocytes from aspired aspirated mature follicles (3–6 mm diameter) were obtained from a local abattoir. During the last 24 h of maturation, oocytes (n = 1303) were placed into maturation media supplemented either 1% (vol/vol) or 5% (vol/vol) thawed snap-frozen oviducal fluid. Fertilization was performed using pooled frozen-thawed semen from 3 different boars. During IVF, the fertilization medium was supplemented with 1% (vol/vol) or 5% (vol/vol) oviducal fluid. Fertilization characteristics were evaluated 12 h after IVF and rates of embryonic cleavage and blastocyst development were observed at 48 and 144 h after IVF, respectively. Data were analysed using ANOVA with the main effects including treatment, well, and replicate. Chi-square analysis was used to determine percentages of embryos reaching the different developmental stages for each treatment. There were no significant differences in the percentages of oocytes that reached metaphase II by the end of maturation or in sperm penetration rates after IVF. However, oocytes treated with 1% (vol/vol) oviducal fluid during the end of maturation and IVF (33.33 ± 2.61) and 5% (vol/vol) oviducal fluid during maturation (33.33 ± 2.66) or IVF (39.53 ± 3.78) had significantly less (P < 0.05) incidence of polyspermic penetrations and a significantly higher (P < 0.05) incidence of male pronuclear formation (87.50 ± 4.01; 86.67 ± 4.83; 86.05 ± 3.19, respectively) compared with no oviducal fluid supplementation. Oocytes supplemented with 5% (vol/vol) oviducal fluid during maturation and IVF had significantly lower (P < 0.05) incidences of polyspermic penetration (27.91 ± 2.50) and significantly higher (P < 0.05) percentages of embryos reaching the 2-cell stage (81.76 ± 3.72) and blastocyst stage of development (37.74 ± 1.09) by 48 and 144 h, respectively, compared with all other groups. The results of this study suggest that supplementing 5% (vol/vol) oviducal fluid during maturation and IVF improves the success rates of in vitro embryo development in pigs.

scholarly journals 160EFFECTS OF EXTRACELLULAR ION CONCENTRATIONS ON IN VITRO DEVELOPMENT OF DOMESTIC CAT IVF EMBRYOS

2004 ◽  
Vol 16 (2) ◽  
pp. 202 ◽  
Author(s):  
W.F. Swanson ◽  
A.L. Manharth ◽  
J.B. Bond ◽  
H.L. Bateman ◽  
R.L. Krisher ◽  
...  
Keyword(s):  
Culture Media ◽  
Ionic Composition ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Domestic Cat ◽  
Embryo Viability ◽  
Blastocyst Development ◽  
In Vitro Development ◽  
Vitro Development

Domestic cat embryos typically are cultured in media formulated for somatic cells or embryos from rodents or livestock species. Under these conditions, blastocyst development has been inconsistent and delayed relative to embryos grown in vivo, and embryo viability following transfer has been low. Our goal is to systematically define the culture requirements of the feline embryo to improve embryo development and viability. The objective of this study was to determine the ionic (NaCl, KCl, KH2PO4, and CaCl2:MgSO4) preferences of domestic cat IVF embryos. Anestral female cats were injected (i.m.) with 150IU eCG followed 84h later by 100IUhCG. Oocytes were recovered via laparoscopic follicular aspiration approximately 24h post-hCG injection (Day 0). Semen was collected from one of two males by means of an artificial vagina and washed once in HEPES-buffered IVF medium. Mature cumulus-oocyte complexes were co-incubated with 2.5–5×105 motile sperm mL−1 in IVF medium (100mM NaCl, 4.0mM KCl, 1.0mM KH2 PO4, 2.0mM CaCl2, 1.0mM MgSO4-7H2O, 25.0mM NaHCO3, 3.0mM glucose, 0.1mM pyruvate, 6.0mM L-lactate, 1.0mM glutamine, 0.1mM taurine, 1×MEM nonessential amino acids, 50μgmL−1 gentamicin, and 4.0mgmL−1 BSA) for 19 to 22h in 6% CO2 in air (38.7°C). Cumulus cells were removed and embryos cultured (8–11 embryos/50μL drop; 6% CO2, 5% O2, 89% N2, 38.7°C) in media containing 100.0 or 120.0mM NaCl, 4.0 or 8.0mM KCl, 0.25 or 1.0mM KH2PO4, and 1.0mM:2.0mM or 2.0mM:1.0mM CaCl2:MgSO4 (2×2×2×2 factorial design). The remaining components of the culture medium were identical to the IVF medium (but w/o gentamicin). Development to the blastocyst stage by Day 6, metabolism (glycolysis and pyruvate) of each blastocyst, and final cell number (Hoechst 33342 staining) of all embryos were evaluated. Final cell number of cleaved embryos and development to the blastocyst stage were analyzed using analysis of variance in the GLIMMIX macro of SAS. A total of 236 oocytes were inseminated, yielding 128 cleaved embryos (54%), including 6 blastocysts (4.7% of cleaved embryos). Cell number was not (P&gt;0.05) affected by NaCl, KCl, or KH2PO4 concentrations, but tended (P=0.057) to be higher after culture in 2.0mM:1.0mM CaCl2:MgSO4. Treatments did not significantly affect (P&gt;0.05) development to the blastocyst stage, but numerically more blastocysts were produced in 100.0mM NaCl (4/6), 8.0mM KCl (5/6), or 1.0mM KH2PO4 (5/6). Both CaCl2:MgSO4 ratios resulted in 3 blastocysts. Blastocysts contained 61.08±5.1 (mean±SEM, n=6) cells and actively metabolized glucose (glycolysis, 3.7±0.8pmol/embryo/3h or 0.06±0.01pmol/cell/3h) and pyruvate (0.75±0.27pmol/embryo/3h or 0.013±0.005pmol/cell/3h). These results suggest that the ionic composition of culture media influences the in vitro development of cat IVF embryos. (Supported by NIH grant RR15388.)

Use of time-lapse imaging to evaluate morphokinetics of in vitro equine blastocyst development after oocyte holding for two days at 15°C versus room temperature before intracytoplasmic sperm injection

2019 ◽  
Vol 31 (12) ◽  
pp. 1862 ◽  
Author(s):  
N. A. Martino ◽  
G. Marzano ◽  
A. Mastrorocco ◽  
G. M. Lacalandra ◽  
L. Vincenti ◽  
...  
Keyword(s):  
Embryo Development ◽  
Intracytoplasmic Sperm Injection ◽  
Room Temperature ◽  
Time Lapse ◽  
Blastocyst Stage ◽  
Blastocyst Development ◽  
Cell Stage ◽  
Group 13 ◽  
Time Lapse Imaging

Time-lapse imaging was used to establish the morphokinetics of equine embryo development to the blastocyst stage after invitro oocyte maturation (IVM), intracytoplasmic sperm injection (ICSI) and embryo culture, in oocytes held overnight at room temperature (22–27°C; standard conditions) before IVM. Embryos that developed to the blastocyst stage underwent precleavage cytoplasmic extrusion and cleavage to the 2-, 3- and 4-cell stages significantly earlier than did embryos that arrested in development. We then determined the rate of blastocyst formation after ICSI in oocytes held for 2 days at either 15°C or room temperature before IVM (15-2d and RT-2d treatment groups respectively). The blastocyst development rate was significantly higher in the 15-2d than in the RT-2d group (13% vs 0% respectively). The failure of blastocyst development in the RT-2d group precluded comparison of morphokinetics of blastocyst development between treatments. In any condition examined, development to the blastocyst stage was characterised by earlier cytoplasmic extrusion before cleavage, earlier cleavage to 2- and 4-cell stages and reduced duration at the 2-cell stage compared with non-competent embryos. In conclusion, this study presents morphokinetic parameters predictive of embryo development invitro to the blastocyst stage after ICSI in the horse. We conclude that time-lapse imaging allows increased precision for evaluating effects of different treatments on equine embryo development.

282 IMPROVED QUALITY OF PORCINE BLASTOCYSTS BY AGGREGATION OF EMBRYOS AT THE 4 - 8-CELL STAGE

2006 ◽  
Vol 18 (2) ◽  
pp. 248
Author(s):  
S.-G. Lee ◽  
C.-H. Park ◽  
D.-H. Choi ◽  
H.-Y. Son ◽  
C.-K. Lee
Keyword(s):  
Es Cells ◽  
Embryonic Stem ◽  
Transgenic Animals ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Cell Stage ◽  
Vitro Fertilization

Use of blastocysts produced in vitro would be an efficient way to generate embryonic stem (ES) cells for the production of transgenic animals and the study of developmental gene regulation. In pigs, the morphology and cell number of in vitro-produced blastocysts are inferior to these parameters in their in vivo counterparts. Therefore, establishment of ES cells from blastocysts produced in vitro might be hindered by poor embryo quality. The objective of this study was to increase the cell number of blastocysts derived by aggregating 4–8-cell stage porcine embryos produced in vitro. Cumulus–oocyte complexes were collected from prepubertal gilt ovaries, and matured in vitro. Embryos at the 4–8-cell stage were produced by culturing embryos for two days after in vitro fertilization (IVF). After removal of the zona pellucida with acid Tyrode’s solution, one (1X), two (2X), and three (3X) 4–8-cell stage embryos were aggregated by co-culturing them in aggregation plates followed by culturing to the blastocyst stage. After 7 days, the developmental ability and the number of cells in aggregated embryos were determined by staining with Hoechst 33342 and propidium iodide. The percentage of blastocysts was higher in both 2X and 3X aggregated embryos compared to that of 1X and that of intact controls (Table 1). The cell number of blastocysts also increased in aggregated embryos compared to that of non-aggregated (1X) embryos and controls. This result suggests that aggregation might improve the quality of in vitro-fertilized porcine blastocysts by increasing cell numbers, thus becoming a useful resource for isolation and establishment of porcine ES cells. Further studies are required to investigate the quality of the aggregated embryos in terms of increasing the pluripotent cell population by staining for Oct-4 and to apply improved aggregation methods in nuclear-transferred (NT) porcine embryos. Table 1. Development, cell number, and ICM ratio of aggregated porcine embryos

144 USE OF A NOVEL BOVINE EMBRYO CULTURE MEDIUM TO IMPROVE BLASTOCYST DEVELOPMENT AND SURVIVAL FOLLOWING VITRIFICATION

2010 ◽  
Vol 22 (1) ◽  
pp. 231
Author(s):  
J. Block ◽  
L. Bonilla ◽  
P. J. Hansen
Keyword(s):  
Amino Acids ◽  
Culture Medium ◽  
Essential Amino Acids ◽  
Blastocyst Stage ◽  
Bovine Embryo ◽  
Blastocyst Development ◽  
Cleavage Rate ◽  
Fresh Embryos ◽  
Hatching Rates

The objective of the present study was to determine whether culture of bovine embryos in a proprietary serum-free culture medium, Block-Bonilla-Hansen-7 (BBH-7), could improve development to the blastocyst stage and enhance survival following vitrification. For Exp. 1, embryos were produced in vitro and cultured in BBH-7 or modified synthetic oviductal fluid (mSOF; as in zygote 10:341 except with 10 μL mL-1 of nonessential amino acids, 20 μL mL-1 of essential amino acids, and 1 mg mL-1 of polyvinyl alcohol instead of albumin) in 5% (v/v) oxygen. Grade 1 expanded blastocysts were harvested at Day 7 post-insemination and vitrified using the open-pulled straw method (Vagta et al. 1998 Mol. Reprod. Dev. 51, 53-58). Vitrified embryos were thawed and cultured in vitro in either mSOF or BBH-7 supplemented with 10% fetal bovine serum and 50 μM dithiolthreitol. Re-expansion and hatching rates were recorded at 24, 48, and 72 h post-thaw. There was no effect of culture medium on cleavage rate. The proportion of oocytes that developed to the blastocyst and advanced blastocyst stages (expanded, hatching, and hatched) at Day 7 was higher (P < 0.001) for embryos cultured in BBH-7 than for embryos cultured in mSOF (41.9 ± 2.0 v. 14.7 ± 2.0% and 31.1 ± 1.3 v. 6.4 ± 1.3%, respectively). There was no effect of culture medium on re-expansion rates at 24, 48, and 72 h post-thaw or on hatching rates at 48 or 72 h. However, the proportion of embryos that were hatching or had hatched by 24 h post-thaw was higher (P < 0.001) for BBH-7 than for mSOF (59.0 ± 0.5 v. 26.7 ± 0.5%). For Exp. 2, late lactation and/or repeat breeder, lactating Holstein cows were synchronized for timed embryo transfer using the OvSynch-56 protocol. Embryos were produced in vitro and cultured in BBH-7 in 5% (v/v) oxygen. Vitrified embryos were produced as for Exp. 1. Fresh embryos were grade 1 expanded blastocysts harvested at Day 7 after insemination. A single embryo was transferred at Day 7 after putative ovulation to all cows with a corpus luteum confirmed by ultrasonography. Pregnancy was diagnosed at Day 28-30 of gestation by ultrasonography. There was no difference in the proportion of recipients that became pregnant after receiving either a fresh (7/18 = 39%) or vitrified (10/27 = 37%) embryo cultured in BBH-7. The results of the present study indicate that BBH-7 can be used to increase the proportion of oocytes that develop to the blastocyst stage. Moreover, the results demonstrate that vitrified embryos produced after culture in BBH-7 can achieve pregnancy rates similar to those obtained using fresh embryos. Support: USDA 2006-55203-17390 and Southeast Milk Checkoff Program.

125 EXAMINING CRITERIA FOR EXTENDING BOVINE BLASTOCYST SURVIVAL IN VITRO

2008 ◽  
Vol 20 (1) ◽  
pp. 143
Author(s):  
F. N. T. Cooke ◽  
T. M. Rodina ◽  
P. J. Hansen ◽  
A. D. Ealy
Keyword(s):  
Conditioned Medium ◽  
Culture System ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Bovine Embryo ◽  
Blastocyst Development ◽  
Interferon Tau ◽  
Cell Numbers ◽  
Bovine Blastocyst

Most of the current culture procedures used for bovine in vitro embryo production terminates at the blastocyst stage. Developing procedures for extending embryo lifespan beyond this phase will provide a valuable tool for understanding events that occur during the second week of pregnancy in cattle. The overall objective of the present studies was to identify culture conditions required to support bovine blastocyst development beyond its initial formation. In the first study, individual day 8 blastocysts (day 0 = day of IVF) were cultured until day 11 in 30 µL microdrops of Potassium Simplex Optimized Medium-Bovine Embryo 2 containing 0.1 mm non-essential amino acids or Tissue Culture Medium 199 (M199). Both media were supplemented with 5% [v/v] fetal bovine serum (FBS) and incubations were in an atmosphere of either 5 or 21% (v/v) oxygen. A medium by oxygen interaction (P = 0.007) occurred when assessing cell number on day 11. Blastocysts cultured in M199 and in a 5% O2 environment had greater (P < 0.002) cell numbers (536 � 49) than blastocysts incubated in other conditions (339 � 28). Conditioned medium from blastocysts incubated in 21% O2 contained greater (P < 0.05) concentrations of bioactive interferon-tau (IFNT) than blastocysts incubated in 5% O2 regardless of medium type (70.5 � 28 v. 17.2 � 2.6 ng mL–1). In a follow-up study, blastocysts could remain morphologically viable through day 11 in M199 containing at least 2.5% FBS. To examine whether oxidative stress was responsible for the increase in IFNT production under 21% O2, blastocysts were incubated under a 5% O2 atmosphere in M199 containing 2.5% FBS and increasing concentrations of tert-butylhydroperoxide (tBH), a membrane-permeable oxidative agent. Addition of e3 nm tBH decreased cell numbers but did not increase IFNT concentrations in conditioned medium. To examine whether blastocysts could survive beyond day 11 in culture, day 11 blastocysts were transferred to 400 �L of M199 with 20% FBS under 5% oxygen and cultured from day 11 to 20–21 post-IVF. Half of the medium was replaced every 2–3 days. On day 13–14, 16.6 � 6.1% of blastocysts showed initial signs of degeneration. A portion of blastocysts (32.9 � 9.6%) began attaching to plates on days 13–15 and produced outgrowths that appeared viable on days 20–21. All of the non-attached blastocysts degenerated by day 17–18. No blastocyst elongation was detected. In conclusion, a culture system was developed that sustains blastocyst viability and IFNT production in vitro to day 11. Although this culture system allowed blastocyst survival until day 14, normal conceptus development (i.e. elongation/filamentation) was not achieved. Nonetheless, the culture system provides a useful tool for examining the initial stages of blastocyst development and IFNT production from individual bovine embryos.

82 EARLY PORCINE EMBRYO ENERGY PREFERENCE AND SUBSEQUENT DEVELOPMENT

2016 ◽  
Vol 28 (2) ◽  
pp. 170
Author(s):  
L. D. Spate ◽  
B. K. Redel ◽  
R. S. Prather
Keyword(s):  
Energy Source ◽  
Subsequent Development ◽  
Cell Number ◽  
Total Cell ◽  
Control Medium ◽  
Blastocyst Development ◽  
Total Cell Number ◽  
Cell Stage ◽  
Porcine Embryo

Early porcine embryo metabolism in vitro is not completely understood. It has been suggested that before embryo genome activation (4-cell stage), the preferred energy source of the embryo is pyruvate. In our porcine zygote culture medium (MU1), the energy sources are 0.2 mM pyruvate and 2.0 mM calcium lactate. Three experiments were performed with in vitro-matured and IVF embryos to examine the effect on blastocyst development after withholding pyruvate and/or lactate during the first 48 h of culture. In Experiment 1, embryos were cultured without lactate for 48 and then cultured to Day 6 in control medium containing lactate. Control embryos were cultured in medium with lactate starting after fertilization to Day 6. All data were analysed by using SAS 9.3 with a GENMOD procedure used for the blastocyst data and a GLM procedure used for the cell number data. On Day 6, the percentage of embryos that formed blastocysts was 30.2% for control and 26.5% for embryos cultured for 48 h without lactate (n = 490, 4 replications). The difference was not significant P > 0.05. In Experiment 2, embryos were cultured without pyruvate for 48 and then cultured to Day 6 in control medium containing pyruvate. Control embryos were cultured in medium with pyruvate starting after fertilization to Day 6. On Day 6, the percentage of embryos that formed blastocysts was 31.1% for control and 30.5% for embryos cultured for 48 h without pyruvate (n = 385, 3 replications). In Experiment 3, embryos were cultured in control medium for the first 48 h and then cultured to Day 6 in medium without pyruvate, thus forcing the embryos to use lactate instead of pyruvate. On Day 6, the percentage of embryos that formed blastocysts in the pyruvate free medium increased from 28.6%a ± 1.0 to 33.9%b ± 1.0; P ≤ 0.05 (n = 490, 4 replications) compared with the control and total cell number increased from 30.7a ± 1.5 to 41.3b ± 1.8 cells, respectively; P ≤ 0.05 (n = 65, 4 replications). The results from Experiments 2 and 3 were unanticipated as it was believed that the embryo would be more dependent on pyruvate for energy up to the blastocyst stage. We believed in Experiment 2 that from zygote to 4 cells the embryos were not as capable of using lactate and that removing the pyruvate would hinder further development. In Experiment 3, forcing the embryo to use lactate from Day 2 to Day 6 significantly improved blastocyst development and total cell number, suggesting that the embryo is not dependent on a specific energy source or that there are adequate pyruvate stores in the oocyte to 4-cell stage, to promote development to blastocyst. Funding was provided by Food for the 21st Century, the University of Missouri, and the National Institutes of Health (OD011140).

Some effects of genotype and composition of the culture medium on the development of mouse zygotes in vitro

1993 ◽  
Vol 5 (4) ◽  
pp. 405 ◽  
Author(s):  
ZF Du ◽  
RG Wales
Keyword(s):  
Culture Medium ◽  
Blastocyst Stage ◽  
Blastocyst Development ◽  
Cell Stage ◽  
Reciprocal Crosses ◽  
Maternal Genome ◽  
Zygote Development ◽  
Mouse Zygotes ◽  
Better Than

The effects of EDTA and the presence of glucose and glutamine in CZB medium on the development of mouse zygotes of different genotype were investigated. Although 30-80% of zygotes (depending on the cross) passed the 2-cell stage in EDTA-free medium, the addition of a low concentration of EDTA was necessary in these experiments to obtain blastocysts in culture. In reciprocal crosses between outbred (Qs), inbred (DBA/2) and hybrid (B10D2F1) stock, there was evidence of a strong influence of the maternal genome on zygote development, with those from B10D2F1 females performing best irrespective of sire. A paternal influence on development was also evident but the most successful sire varied with the genotype of female used and reciprocal crosses differed greatly in the ability of the resultant zygote to develop in culture. For zygotes recovered from Qs females, CZB medium containing glucose and glutamine supported development to the blastocyst stage better than did medium devoid of these substrates. Tests with embryos from B10D2F1 females indicated that the presence of glucose for the whole or for part of the incubation period stimulated blastocyst development. However, the addition of glutamine to the medium in these tests had no significant effect on the development of blastocysts.

scholarly journals Leptin has concentration and stage-dependent effects on embryonic development in vitro

Reproduction ◽  
2006 ◽  
Vol 132 (2) ◽  
pp. 247-256 ◽  
Author(s):  
Muren Herrid ◽  
Van Ly Nguyen ◽  
Geoff Hinch ◽  
James R McFarlane
Keyword(s):  
Embryonic Development ◽  
Embryo Development ◽  
Culture Medium ◽  
Leptin Receptor ◽  
Inhibitory Effect ◽  
Differential Sensitivity ◽  
Cell Stage ◽  
Paracrine Signalling ◽  
Stage Of Development

There is accumulating evidence that leptin may be directly involved in pre-implantation embryonic development, however, it is unclear whether there is a concentration and stage-dependent regulatory pattern. In this study, the addition of 10 ng/ml human recombinant leptin to the culture medium significantly increased the percentage of two-cell mouse embryos that developed into blastocysts and hatched blastocysts, whereas in the presence of 100 ng/ml leptin, the development rate was significantly inhibited. The total cell numbers in the hatched blastocysts were significantly higher in the presence of 10 ng/ml leptin compared with controls and higher concentrations. The differential sensitivity to leptin was found to vary among embryos at different stages of development. Supplementation of leptin (10 ng/ml) to culture medium at two- to eight-cell stages resulted in a consistent stimulatory effect on embryo development. Most interestingly, the inhibitory effect of high leptin concentration (100 ng/ml) on embryo development was diminished when it was added to the culture medium at the eight-cell stage of development. The concentration-dependent regulation pattern was confirmed using sheep embryos, under similar conditions although sheep embryos appeared to be more sensitive in responding to leptin. Having established the effect of exogenous leptin on embryo development, the expression pattern of leptin and its receptors were also investigated. Leptin mRNA was not detected in mouse two-, four-, eight-cell and blastocyst stage embryos, whereas three isoforms of leptin receptor (Ob-Ra, Ob-Rb and Ob-Re) were identified in these cells, indicating that leptin is likely to modulate embryo development via a paracrine signalling system.

scholarly journals 276INFLUENCE OF SPERM TREATMENTS ON BLASTOCYST DEVELOPMENT IN VITRO AND CELL NUMBER IN CATTLE

2004 ◽  
Vol 16 (2) ◽  
pp. 258
Author(s):  
B.G. Jeon ◽  
J.S. Moon ◽  
K.C. Kim ◽  
G.J. Rho
Keyword(s):  
Silicone Oil ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Glass Wool ◽  
Hatching Rate ◽  
Blastocyst Development ◽  
Serum Free ◽  
Cell Numbers ◽  
Bull Sperm

Experiments were designed to examine the effects of developmental rate and cell numbers in embryos produced by in vitro fertilization (IVF) using sperm from 2 bulls (sperm A and B purchased from commercial sale) isolated by three methods. Cumulus-oocyte-complexes collected from ovaries harvested from a local slaughter house were matured in 50μL droplets of serum-free M199 medium supplemented with 1μgmL−1 estradiol-17β, 10μgmL−1 LH and FSH under silicone oil at 39°C in a humidified atmosphere of 5% CO2 in air. After 24h of culture, oocytes were fertilized with the sperm treated by three different methods of isolation;; percoll gradient, swim-up and glass wool filtration;; a final concentration of 2×106 cells mL−1 was used. At 16h after fertilization, presumptive zygotes were co-cultured in serum-free M199 with BOEC for up to 192h post-insemination. At 48h and 120h post-insemination, the cultures were fed with 25μL of serum-free M199. The embryos were compared for their rates of cleavage at 48h post-insemination, development to the blastocyst stage, and hatching, and also the cell number at 192h post-insemination. Differences between treatments were analyzed using one-way ANOVA after arc-sine transformation of the proportional data of cleavage, development into blastocyst stage and hatching. Comparisons of means among treatments were performed using Tukey-Kramer multiple comparisons test. The results are summarized below. The rates of cleavage in embryos produced by IVF using sperm from 2 bulls isolated by percoll, swim-up and glass wool were not significantly different. The blastocyst development and hatching rates between sperm treatment were not significant within bull sperm A and within sperm B. However, although the hatching rate in percoll treatment of bull sperm A was higher than in bull sperm B, the difference was not statistically significant. The mean cell numbers in percoll treatment of bull sperm A (176.5±7.1) were significantly higher (P&lt;0.001) than the others. In bull sperm B the cell numbers in percoll treatment were higher than the other two treatments, but the differences were not statistically significant. In conclusion, these results support the concept that sperm preparation using percoll has beneficial effects on blastocyst cell number. Table 1 Developmental rates of in vitro embryos using sperm from 2 bulls isolated by three methods with 4 replicates

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