scholarly journals Controlled spermatozoa–oocyte interaction improves embryo quality in sheep

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Debora Agata Anzalone ◽  
Luca Palazzese ◽  
Marta Czernik ◽  
Annalaura Sabatucci ◽  
Luca Valbonetti ◽  
...  
Keyword(s):  
Embryo Quality ◽  
Time Frame ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Free Oxygen Radicals ◽  
High Concentration ◽  
Cell Stage ◽  
Vitro Fertilization ◽  
Set Up

AbstractThe current protocols of in vitro fertilization and culture in sheep rely on paradigms established more than 25 years ago, where Metaphase II oocytes are co-incubated with capacitated spermatozoa overnight. While this approach maximizes the number of fertilized oocytes, on the other side it exposes them to high concentration of reactive oxygen species (ROS) generated by active and degenerating spermatozoa, and positively correlates with polyspermy. Here we set up to precisely define the time frame during which spermatozoa effectively penetrates and fertilizes the oocyte, in order to drastically reduce spermatozoa-oocyte interaction. To do that, in vitro matured sheep oocytes co-incubated with spermatozoa in IVF medium were sampled every 30 min (start of incubation time 0) to verify the presence of a fertilizing spermatozoon. Having defined the fertilization time frame (4 h, data from 105 oocytes), we next compared the standard IVF procedures overnight (about 16 h spermatozoa/oocyte exposure, group o/nIVF) with a short one (4 h, group shIVF). A lower polyspermic fertilization (> 2PN) was detected in shIVF (6.5%) compared to o/nIVF (17.8%), P < 0.05. The o/nIVF group resulted in a significantly lower 2-cell stage embryos, than shIVF [34.6% (81/234) vs 50.6% (122/241) respectively, P < 0.001]. Likewise, the development to blastocyst stage confirmed a better quality [29% (70/241) vs 23.5% (55/234), shIVF vs o/nIVF respectively] and an increased Total Cell Number (TCN) in shIVF embryos, compared with o/n ones. The data on ROS have confirmed that its generation is IVF time-dependent, with high levels in the o/nIVF group. Overall, the data suggest that a shorter oocyte-spermatozoa incubation results in an improved embryo production and a better embryo quality, very likely as a consequence of a shorter exposure to the free oxygen radicals and the ensuing oxidative stress imposed by overnight culture.

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

280 PORCINE BLASTOCYSTS DERIVED FROM IN VITRO-MATURED OOCYTES INJECTED INTRACYTOPLASMICALLY WITH SPERM FROM TESTICULAR TISSUE XENOGRAFTED INTO NUDE MICE

2006 ◽  
Vol 18 (2) ◽  
pp. 247 ◽  
Author(s):  
K. Kikuchi ◽  
M. Nakai ◽  
N. Kashiwazaki ◽  
M. Ozawa ◽  
N. Maedomari ◽  
...  
Keyword(s):  
Nude Mice ◽  
New Technology ◽  
Testicular Tissue ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Embryo Production ◽  
Vitro Fertilization ◽  
Male Gametes ◽  
Sperm Suspension

The utilization of spermatogonia from testicular tissue after xenografting into immuno-deficient mice should lead to new insights for the conservation of male gametes. However, successful embryo production using sperm cells from xenografted testicular tissues has been limited to rhesus monkeys (Honaramooz et al. 2004 Biol. Reprod. 70, 1500-1503). In the present study, the objective was to establish this new technology for pig conservation in combination with intracytoplasmic sperm injection. Testes were obtained from male piglets 6 to 15 days old, in which most of the germ cells were gonocytes; these were minced into pieces of approximately 1.5 � 1.5 � 1.5 mm. Approximately 20 fragments were transplanted under the back skin of castrated nude mice 5 to 8 weeks old. The testicular grafts were recovered between 125 and 192 days after xenografting, minced in Dulbecco's phosphate-buffered saline, and centrifuged several times, to serve as a sperm suspension. In vitro maturation of the recipient oocytes (Kikuchi et al. 2002 Biol. Reprod. 66, 1033-1041) and injection with an intact spermatozoon, followed by electrical stimulation at 1 h post-injection (Nakai et al. 2003 Biol. Reprod. 68, 1003-1008), were carried out. The putative zygotes were cultured in vitro for 6 days (Kikuchi et al. 2002), and were then fixed, stained, and assessed for embryonic development and quality. From a total of 27 mice that were xenografted with testicular tissues, spermatids and spermatozoa were obtained in 19 of the mice (70.4%). Most of the spermatozoa were matured morphologically, showing faint motility after release into the collection medium. From a total of 253 oocytes (four replications) that were injected with sperm, 63 (24.9 � 7.1%) oocytes developed to the blastocyst stage. The average total cell number was 41.9 � 3.9. These values are comparable to those in in vitro fertilization by frozen-thawed spermatozoa, resulting in developmental ability to piglets after embryo transfer (25.3% and 48.7 cells; Kikuchi et al. 2002). These results suggest the possibility of embryo production using porcine spermatozoa that are differentiated from gonocytes within the xenografts.

Effect of protein supplementation on development to the hatching and hatched blastocyst stages of cat IVF embryos

2002 ◽  
Vol 14 (5) ◽  
pp. 291 ◽  
Author(s):  
N. W. Kurniani Karja ◽  
Takeshige Otoi ◽  
Masako Murakami ◽  
Minori Yuge ◽  
Mokhamad Fahrudin ◽  
...  
Keyword(s):  
Bovine Serum ◽  
Culture Medium ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Early Embryo ◽  
Protein Supplementation ◽  
Vitro Fertilization ◽  
Fetal Bovine ◽  
The Mean

The effects of protein supplementation in culture medium on development to the hatching and hatched blastocyst stages of cat in vitro-fertilized embryos were investigated. In the first experiment, presumptive zygotes derived from in vitro maturation and in vitro fertilization (IVF) were cultured in modified Earle's balanced salt solution (MK-1) supplemented with 0.4% bovine serum albumin (BSA) or 5% fetal bovine serum (FBS) for 9 days. There were no significant differences between the BSA and FBS groups with respect to the proportion of cleavage and development to the morula and blastocyst stages of zygotes. However, the presence of FBS in the medium enhanced development to the hatching blastocyst stage of zygotes compared with the BSA group (31.4% v. 7.8%). Moreover, 2.9% of zygotes cultured with FBS developed to the hatched blastocyst stage. The mean cell number of blastocysts derived from zygotes cultured with FBS was significantly higher (P&lt;0.01) than that from zygotes cultured with BSA (136.6 v.101.5). In the second experiment, embryos at the morula or blastocyst stage, which were produced by culturing in MK-1 supplemented with 0.4% BSA after IVF, were subsequently cultured in MK-1 with 0.4% BSA or 5% FBS. Significantly more morulae developed to the blastocyst (P&lt;0.05) and hatching blastocyst stages (P&lt;0.01) in the FBS group than in the BSA group (71.5% and 53.6% v. 44.9% and 6.0%, respectively). Although none of the morulae cultured with BSA developed to the hatched blastocyst stage, 11.5% of morulae cultured with FBS developed to the hatched blastocyst stage. Moreover, the proportion of development to the hatching blastocyst stage of blastocysts was significantly higher (P&lt;0.01) in the FBS group than in the BSA group (68.7% v. 9.8%). None of the blastocysts cultured with BSA developed to the hatched blastocyst stage, whereas 7.3% of blastocysts cultured with FBS developed to the hatched blastocyst stage. The results of the present study indicate that supplementation with FBS at different stages of early embryo development promotes development to the hatching and hatched blastocyst stages of cat IVF embryos.

scholarly journals 152EFFECT OF REPLACEMENT OF PYRUVATE/LACTATE IN CULTURE MEDIUM WITH GLUCOSE ON PREIMPLANTATION DEVELOPMENT OF PORCINE EMBRYOS IN VITRO

2004 ◽  
Vol 16 (2) ◽  
pp. 198
Author(s):  
N.W.K. Karja ◽  
S. Medvedev ◽  
D. Fuchimoto ◽  
A. Onishi ◽  
M. Iwamoto ◽  
...  
Keyword(s):  
Energy Source ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Culture Period ◽  
Blastocyst Formation ◽  
Cell Stage ◽  
Energy Substrates ◽  
Anova Test

Kikuchi et al. (2002 Biol. Reprod. 66, 1033–1041) reported that replacement of pyruvate and lactate with glucose, as energy substrates, at 48h of culture in IVC medium enhanced the quality of IVP porcine blastocysts. However, the exact time during early cleavage stages when the utilization of glucose as an energy source is optimal has not yet been determined. The purpose of this study was to examine the effects of glucose supplementation at different times of culture on the developmental competence of IVP porcine embryos. Porcine cumulus-oocytes complexes were matured in modified NCSU-37 solution and fertilized in vitro according to Kikuchi et al. All cultures were performed at 38.5°C, 5% O2, 5% CO2, and 90% N2. In experiment 1, after being fertilized (Day 0), putative zygotes (1158 in 6 trials) were cultured in NCSU-37 supplemented with 0.4% BSA, 0.17mM sodium pyruvate, and 2.73mM sodium lactate (IVC-pyr/lac). Embryos (30–50 in each group) were then transferred into NCSU-37 supplemented with 0.4% BSA and 5.55mM D-glucose (IVC-glu) at 24, 48, 72, 96, or 118h of culture. As control groups, putative zygotes (391) were cultured in IVC-pyr/lac or IVC-glu for the whole culture period. In experiment 2, after being fertilized, putative zygotes (543 in 4 trials, 30–50 in each group) were cultured in IVC-pyr/lac, and then were transferred into IVC-glu at 48h, 53h, 58h, or 63h of culture, because glycolytic activity of in vitro-derived porcine embryos was reported to increase around the 8-cell stage, and some embryos develop to that stage before 72h of culture in experiment 1. All embryos were cultured for 6 days, and then development to the blastocyst stage and number of cells per blastocyst were assessed. When IVF embryos were cultured in IVC pyr/lac for 24h or 48h and subsequently in IVC-glu until day 6 in experiment 1, the rates of blastocyst formation were significantly higher (P&lt;0.05, ANOVA test) than those of embryos cultured in IVC-pyr/lac for the whole culture period (24.4% and 23.0% v. 14.5%, respectively). However, when IVC pyr/lac was replaced with IVC-glu, there were no significant differences between the energy source replacement groups and the glucose-only group in terms of the proportions of cleavage, development to the blastocyst stage and mean cell number per blastocyst (P&gt;0.05, ANOVA test) (15.2%–24.4%, and 16.8%, respectively). Replacement of pyruvate and lactate with glucose at 58h of culture in experiment 2 significantly enhanced the rate of blastocyst formation (P&lt;0.05, ANOVA test) but not the mean cell number compared with zygotes in which the replacement was done at 48, 53, and 63h of culture (31.3% v. 20.6%, 20.8%, and 21.1%, respectively) (P&lt;0.05, ANOVA test). In conclusion, replacement of pyruvate and lactate with glucose as energy substrates was optimal at 58h of culture for the in vitro development of pig embryos to the blastocyst stage.

scholarly journals Development of Preimplantation Mouse Embryos in vivo and in vitro

1982 ◽  
Vol 35 (2) ◽  
pp. 187 ◽  
Author(s):  
GM Harlow ◽  
P Quinn
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Culture Conditions ◽  
Cell Stage ◽  
Preimplantation Mouse ◽  
Development In Vitro

The culture conditions for the development in vitro of (C57BL/6 X CBA) F2 hybrid two-cell embryos to the blastocyst stage have been optimized. Commercially available pre-sterile disposable plastic culture dishes supported more reliable development than re-usable washed glass tubes. The presence of an oil layer reduced the variability in development. An average of 85 % of blastocysts developed from hybrid two-cell embryos cultured in drops of Whitten's medium under oil in plastic culture dishes in an atmosphere of 5% O2 : 5% CO2 : 90% N2 ? The time taken for the total cell number to double in embryos developing in vivo was 10 h, and in cultured embryos 17 h. Embryos cultured in vitro from the two-cell stage to blastocyst stage were retarded by 18-24 h in comparison with those remaining in vivo. Day-4 blastocysts in vivo contained 25-70 cells (mean 50) with 7-28 (mean 16) of these in the inner cell mass. Cultured blastocysts contained 19-73 cells (mean 44) with 8-34 (mean 19) of these in the inner cell mass. In the uterine environment, inner-cell-mass blastomeres divided at a faster rate than trophectoderm blastomeres and it is suggested that a long cell cycle is associated with terminal differentiation. Although cultured blastocysts and inner cell masses contained the same number of cells as blastocysts and inner cell masses in vivo, the rate of cell division in cultured inner cell masses was markedly reduced.

scholarly journals 25 IN VITRO DEVELOPMENT OF AGGREGATED NUCLEAR TRANSFERRED EMBRYOS DERIVED FROM BOVINE CUMULUS CELLS

2005 ◽  
Vol 17 (2) ◽  
pp. 162
Author(s):  
S. Akagi ◽  
B. Tsuneishi ◽  
S. Watanabe ◽  
S. Takahashi
Keyword(s):  
Zona Pellucida ◽  
Cumulus Cells ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Cell Stage ◽  
In Vitro Development ◽  
Functional Peptide ◽  
Vitro Development

It has been reported that aggregation of two nuclear transfer (NT) mouse embryos shows an improvement in full-term development (Boiani M et al. 2003 EMBO J. 22, 5304–5312). In this study, we examined the effect of aggregation on in vitro development of bovine NT embryos. As donor cells for NT, cumulus cells of passage 3–5 were used following culture in serum-starved medium for 5–7 days. NT was performed as previously described (Akagi S et al. 2003 Mol. Reprod. Dev. 66, 264–272). NT embryos were cultured in a serum-free medium (IVD-101, Research Institute of Functional Peptide Co., Ltd., Shimojo, Yamagat, Japan). Eight-cell-stage embryos on Day 2 or 16- to 32-cell-stage embryos on day 4 were used for embryo aggregation after removal of the zona pellucida. A small depression was made in a 25-μL drop of TCM-199 with 50 μg/mL phytohemagglutinin (TCM199/PHA) or IVD-101 using a darning needle. Two or three NT embryos were placed into the depression in the drop of TCM199/PHA for 20 min. NT aggregates were then moved into the depression in the drop of IVD-101 and cultured until Day 7. In vitro development of NT aggregates was summarized in Table 1. There were no differences in the cell number and ICM ratio of blastocysts between non-aggregated zona-intact and zona-free embryos. All aggregates of three NT embryos developed to the blastocyst stage and the cell number of these blastocysts was significantly higher than that of non-aggregated NT blastocysts. These results indicate that removal of the zona pellucida does not affect the cell number and ICM ratio of blastocysts and that aggregates of three NT embryos can develop to blastocysts with high cell numbers which are equivalent to in vivo-derived embryos (166 ± 11, Knijn HM et al. 2003 Biol. Reprod. 69, 1371–1378). Table 1. Development, cell number, and ICM ratio of NT aggregates

75 Culture of isolated blastomeres supplemented with L-ascorbic acid 2-phosphate in a well-of-the-well culture dish

2019 ◽  
Vol 31 (1) ◽  
pp. 163
Author(s):  
Y. Hasiyada ◽  
H. Matsuda ◽  
Y. Aikawa ◽  
M. Ohtake ◽  
T. Yamanouchi
Keyword(s):  
Formation Rate ◽  
Calf Serum ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Blastocyst Formation ◽  
Culture Dish ◽  
Cell Stage ◽  
Quality Grade

We have reported monozygotic twin calves that can be produced efficiently by blastomere separation of 2-cell stage embryos and by the use of a commercially provided well-of-the-well culture dish (Hashiyada 2017 J. Reprod. Dev.). The present study was conducted to evaluate the effect of a culture supplement, l-ascorbic acid 2-phosphate (AA-2P), a sustained antioxidant substance that reduces reactive oxygen species. Embryos were produced using oocytes from ovaries collected at an abattoir by in vitro maturation, IVF, and in vitro culture (IVC). TCM199 supplemented with 5% calf serum, Brackett-Oliphant solution supplemented with 10mg mL−1 BSA, and CR1aa containing 5% calf serum were used for each culture step. Two-cell stage embryos were obtained 24 to 27h post-insemination (hpi). Zonae pellucidae were removed by exposure to 0.25% pronase. Then, embryos were separated into each blastomere by gentle pipetting in IVC medium. Each blastomere was introduced into a single conical micro-well of 25 wells, each having a diameter and depth of ~287 and 168µm (Dai Nippon Printing, Tokyo, Japan). Culture of blastomeres in wells was performed covered with a droplet of 2.5 µL/well IVC medium supplemented with 0 (n=212), 250 (n=214), 500 (n=206), and 750 µM (n=204) of AA-2P. The blastocyst formation rate at Day 8 after IVF, the quality of blastocysts assessed by morphological observation, and the cell numbers were compared among each concentration of AA-2P. In addition, the developmental speed to the blastocyst stage was analysed using time-lapse cinematography for 0 and 500 µM of AA-2P (n=40, respectively). Statistical analysis was performed using Fisher’s exact test and ANOVA. The blastocyst formation rate (32-40%), the total cell number (108-114), and inner cell mass cell number (26-28) did not differ among groups. The time to reach the 4-cell stage was significantly shorter in media supplemented with 0 µM (43 hpi) than with 500 µM (52 hpi); however, the time to reach the blastocyst stage did not differ (150 and 155 hpi, respectively). Regarding the proportion of quality grade 1 to 3 blastocysts and the developmental speed to the blastocyst stage, high-quality grade 1 embryos were significantly faster than those of middle and low-quality grade 2 and 3 ones in 0 (145 v. 154 hpi; P&lt;0.05) and 500 µM (150v. 158 hpi; P&lt;0.05) supplemented medium. In this experiment, no effect of AA-2P was observed for the culture of isolated blastomeres from 2-cell stage embryos, although it was suggested that blastomeres with high developmental competence reach the blastocyst stage faster, which might reflect the quality of the embryos.

Cryotolerance of porcine in vitro-produced blastocysts relies on blastocyst stage and length of in vitro culture prior to vitrification

2016 ◽  
Vol 28 (7) ◽  
pp. 886 ◽  
Author(s):  
Roser Morató ◽  
Míriam Castillo-Martín ◽  
Marc Yeste ◽  
Sergi Bonet
Keyword(s):  
In Vitro Culture ◽  
Embryo Quality ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Total Cell ◽  
Apoptotic Cells ◽  
Total Cell Number ◽  
Developmental Potential ◽  
High Degree

The aim of our study was to assess whether the cryotolerance of in vitro-produced embryos could be influenced by the length of in vitro culture and size of blastocoel cavity before vitrification, using the pig as a model. For this purpose we analysed the cryoresistance and apoptosis rate of blastocysts at different stages of development as derived on Day 5 and 6 of in vitro culture. Blastocysts were subsequently vitrified, warmed and cultured for 24 h. Re-expansion rates were recorded at 3 and 24 h and total cell number and apoptotic cells were determined at 24 h. Day-6 blastocysts showed the highest rates of survival after warming, which indicates higher quality compared with Day-5 blastocysts. Higher re-expansion rates were observed for expanded blastocysts and those in the process of hatching when compared with early blastocysts. Total cell number and apoptotic cells were affected by blastocyst stage, vitrification–warming procedures and length of in vitro culture, as expanding and hatching–hatched blastocysts from Day 6 presented higher percentages of apoptotic cells than fresh blastocysts and blastocysts vitrified at Day 5. Our findings suggest that the cryotop vitrification method is useful for the cryopreservation of porcine blastocysts presenting a high degree of expansion, particularly when vitrification is performed after 6 days of in vitro culture. Furthermore, these results show that faster embryo development underlies higher blastocyst cryotolerance and provide evidence that blastocoel cavity expansion before vitrification is a reliable index of in vitro-produced embryo quality and developmental potential.

Exogenous platelet-activating factor stimulates cell proliferation in mouse pre-implantation embryos prior to the fourth cell cycle and shows isoform-specific stimulatory effects

Zygote ◽  
2001 ◽  
Vol 9 (3) ◽  
pp. 261-268 ◽  
Author(s):  
Neil R. Stoddart ◽  
William E. Roudebush ◽  
Steven D. Fleming
Keyword(s):  
Cell Proliferation ◽  
Biological Activities ◽  
Platelet Activating Factor ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Embryonic Cell ◽  
Cell Stage ◽  
Cell Numbers ◽  
Paf Receptor

Mouse embryos secrete molecules homologous to platelet-activating factor (PAF), termed embryo-derived PAF (EPAF), which act in an autocrine/paracrine fashion to stimulate embryonic development in vitro. Mouse EPAF is thought to consist predominantly of hexadecyl (C16) and octadecyl (C18) PAF-like components. Mouse pre-implantation embryos cultured with exogenous PAF from the early cleavage stages exhibit increased blastocyst cell numbers and rates of mitosis around the 8-cell stage. We investigated whether exogenous PAF could specifically stimulate embryonic cell proliferation prior to the blastocyst stage in the mouse and also compared the biological activities of the C16 and C18 PAF isoforms as follows. Embryos were cultured for either 24 h or 120 h from the 2-cell stage and their total cell numbers were determined or their development assessed in terms of their incidence of successful zona-hatching respectively. In each case, embryos were cultured in unsupplemented medium or in medium supplemented with either C16 or C18 PAF (0.5 μM). Compared with controls, culture with C16 PAF produced a significant stimulation of mean total per number per embryo and a significant increase in the incidence of successful zona-hatching, whilst culture with C18 PAF had no significant effect. We then cultured 1-cell zygotes for 48 h in unsupplemented medium or medium supplemented with either an equimolar mixture of C16 and C18 PF or with either C16 or C18 PF alone (each at 0.2 μM). Embryos were also scored for cell number at 4 h and 30 h of culture. Although no significant effect on mean cell number per embryo was seen following 4 h or 30 h of culture with a mixed C16/C18 PAF preparation, culture for 48 h with a mixed C16/C18 PAF preparation or with C16 PAF alone produced a significant increase in mean cell number per embryo compared with controls - an effect that is likely to be receptor-mediated, since culture with an equivalent concentration of C18 PAF had no significant effect compared with controls. We have demonstrated that mouse zygotes/embryos can respond in a specific manner to exogenous hexadecyl PAF in terms of increased rates of cell proliferation prior to cavitation, and must be capable of doing so at some time between the first and third, and also between the second and fourth, cell cycles. Such embryos presumably express one or more classes of functional PAF-receptor molecule during this period (i.e. as early as during the 1-, 2- or 4-cell stages). We have also demonstrated that embryonic response to exogenous PAF is significantly isoform-specific, which may reflect differences between the two isoforms either in affinity for binding to putative embyronic PAF-receptor molecules or in their ability to elicit a stimulatory response following binding. This observation calls into question the use of preparations containing a mixture of hexadecyl and octadecyl PAF isoforms, particularly in dose-response studies, in the mouse.

145 CHANGES IN OXYGEN COMSUMPTION RATES OF EMBRYOS IN KOREAN CATTLE

2010 ◽  
Vol 22 (1) ◽  
pp. 231
Author(s):  
C. Y. Choe ◽  
S. R. Cho ◽  
J. K. Son ◽  
S. H. Choi ◽  
C. Y. Cho ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Embryo Quality ◽  
Blastocyst Stage ◽  
Bovine Embryo ◽  
Bovine Embryos ◽  
Cell Stage ◽  
Significant Difference ◽  
Morula Stage

Oxygen consumption has been regarded as a useful indicator for assessment of mammalian embryo quality. This study was carried out to identify whether oxygen consumption rates measured in bovine embryos using SECM can be used as a standard criteria to evaluate bovine embryo quality. Oxygen consumption of bovine embryos at various developmental stages was measured and analyzed using SECM and ANOVA analysis, respectively. We found that the oxygen consumption significantly increased in blastocyst-stage embryos compared to other stage embryos (from 2-cell stage to morula stage), indicating that oxygen consumption reflects the cell number (5.2-7.6 × 1014 mol-1 s-1 v. 1.2-2.4 × 1014 mol-1 s-1, P < 0.05). There was no significant difference between 2-cell-stage embryos and 8-cell-stage embryos. In the morula-stage embryos, the oxygen consumption of in vivo derived embryos was significantly higher than that of in vitro produced embryos (4.0 × 1014 mol-1 s-1 v. 2.4 × 1014 mol-1 s-1, P < 0.05). However, there was no significant difference in consumption of oxygen by in vivo and in vitro derived bovine blastocyst-stage embryos (P > 0.05). Good-quality embryos with grade 1 or 2 showed significantly higher oxygen consumption than grade 3 or 4 embryos. These results showed that SECM could measure oxygen consumption in bovine embryos and the oxygen consumption could reflect embryonic development stage and embryo quality.

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