93 THE INVOLVEMENT OF E-CADHERIN IN THERMOPROTECTIVE FUNCTION OF INSULIN-LIKE GROWTH FACTOR-1 IN 4-CELL HAMSTER EMBRYOS

2015 ◽  
Vol 27 (1) ◽  
pp. 139
Author(s):  
A. C. Trejo ◽  
I. B. Abad ◽  
V. M. V. Meza ◽  
A. M. Villa ◽  
J. Z. Abad ◽  
...  
Keyword(s):  
Heat Stress ◽  
Growth Factor ◽  
Culture Medium ◽  
Molecular Mechanisms ◽  
Statistical Significance ◽  
Insulin Like Growth Factor ◽  
Cell Stage ◽  
Adhesion Sites ◽  
E Cadherin

Studies have demonstrated that the early pre-implantation embryo is very sensitive to effects of heat stress in vitro. Heat stress reduces the total cell number in blastocysts and increases apoptosis in blastomeres. Insulin-like growth factor-1 (IGF-1) has been widely studied as a thermoprotective agent for its anti-apoptotic actions. Addition of IGF-1 to the culture medium decreases the effects of heat stress on blastocysts but has no effects on 2-cell embryos. Molecular mechanisms by which IGF-1 decreases apoptosis involve activation of the PI3K/Akt pathway. It is also known that adherens junctions contribute to PI3K/AKT activation mediated by the transmembrane glycoprotein E-cadherin, which is involved in Ca2+-dependent cell-cell adhesion. Within 2- to 8-cell embryos, E-cadherin is mainly inactive and has cytoplasmic localization. 6-Dimethylaminopurine (6-DMAP) induces premature cell flattening and E-cadherin redistribution to adhesion sites in 4-cell embryos. The aim of this study was to induce E-cadherin redistribution in 4-cell hamster embryos and evaluate the thermoprotective function of IGF-1 in these embryos. Four-cell embryos were incubated in the presence of 6-DMAP to induce E-cadherin redistribution to adhesion sites and cultured for 24 h under conditions of heat stress and compared with controls without 6-DMAP. Culture medium was supplemented with IGF-1. At the end of culture, developmental stage and rate of apoptosis were determined and analysed by ANOVA using the General Linear Model (GLM) of SAS (SAS Institute Inc., Cary, NC, USA) procedure with statistical significance at P < 0.05. E-Cadherin redistribution induced by 6-DMAP increased development to the 6-cell stage after 24 h (63.57% v. 38.81%, respectively; P < 0.05) and reduced apoptosis (25% v. 33%, respectively; P < 0.05) under heat-stress conditions. In conclusion, we hypothesise a role for E-cadherin-mediated cell flattening in promoting IGF-1-mediated thermoprotection in pre-compact 4-cell hamster embryos. Further studies are required to confirm this link.

scholarly journals 243TEMPORAL DIVERGENCE IN THE PATTERN OF MRNA EXPRESSION IN BOVINE EMBRYOS CULTURED FROM THE ZYGOTE TO BLASTOCYST STAGE IN VITRO OR IN VIVO

2004 ◽  
Vol 16 (2) ◽  
pp. 242
Author(s):  
P. Lonergan ◽  
D. Rizos ◽  
A. Gutierrez-Adan ◽  
P.M. Moreira ◽  
B. Pintado ◽  
...  
Keyword(s):  
Growth Factor ◽  
Relative Abundance ◽  
Transcript Abundance ◽  
Blastocyst Stage ◽  
Insulin Like Growth Factor ◽  
Bovine Embryos ◽  
Interferon Tau ◽  
Cell Stage

The objective of this study was to examine the time during the post-fertilization culture period that gene expression patterns of in vitro cultured bovine embryos diverge from those of their in vivo cultured counterparts. Presumptive bovine zygotes were produced by IVM/IVF of immature oocytes collected from the ovaries of slaughtered animals. At approximately 20h post-insemination (hpi), presumptive zygotes were randomly divided into two culture groups, either in vitro in synthetic oviduct fluid or in vivo, and transferred into the ewe oviduct. Embryos were recovered from both systems at approximately 30hpi (2-cell), two (4-cell), three (8-cell), four (16-cell), five (early morula), six (compact morula) or seven (blastocyst) days pi and snap-frozen for the analysis of transcript abundance using real-time PCR. The transcripts studied were interferon-tau, apoptosis regulator box-a (Bax), connexin 43, sarcosine oxidase, glucose transporter 5, mitochondrial Mn-superoxide dismutase, insulin-like growth factor II, and insulin-like growth factor-I receptor, most of which are known from our previous work to be differentially transcribed in blastocysts derived from culture in vitro or in vivo. Analysis was done on pools of 10 embryos. Data were analyzed using one-way repeated measures ANOVA. The relative abundance of the transcripts studied varied throughout the preimplantation period and was strongly influenced by the culture environment. For example, transcripts for interferon-tau were detected from the 8-cell stage onwards in in vitro-cultured embryos but not until the early morula stage in those cultured in vivo. Levels of this transcript increased significantly at the compact morula and blastocyst stages in both groups but were significantly higher (P&lt;0.05) in in vitro-cultured embryos at both stages. mRNA for Bax was not detected before the 8-cell stage in in vitro cultured embryos and not until the 16-cell stage in in vivo cultured embryos. The abundance of this transcript increased significantly thereafter up to the blastocyst stage in both groups. The level of expression was significantly higher (P&lt;0.05) at all stages of development in in vitro-cultured embryos than those cultured in vivo. The relative abundance of Cx43 transcripts decreased in both in vitro- and in vivo-cultured embryos at the 8- to 16-cell stage. Levels remained low thereafter in the in vitro-cultured embryos but significantly increased in those cultured in vivo. Transcript abundance was significantly higher in in vivo cultured embryos from Day 4 onwards with a ten-fold difference presence at the blastocyst stage. Differences also existed for the other transcripts studied. These data demonstrate that changes in transcript abundance in blastocyst stage embryos are in many cases a consequence of perturbed transcription earlier in development. Depending on the transcript, these differences may be evident in as short as 10h of culture.

166 EFFECTS OF LEPTIN AND IGF-1 ON PRE-IMPLANTATION DEVELOPMENT, DNA FRAGMENTATION, AND GENE EXPRESSION OF BOVINE EMBRYOS CULTURED IN VITRO

2006 ◽  
Vol 18 (2) ◽  
pp. 191
Author(s):  
A. Kaya ◽  
H. Sagirkaya ◽  
M. Misirlioglu ◽  
A. Gumen ◽  
E. Memili ◽  
...  
Keyword(s):  
Growth Factor ◽  
Control Group ◽  
Insulin Like Growth Factor ◽  
Rt Pcr ◽  
Cell Stage ◽  
Group Iii ◽  
Fragmented Dna ◽  
Group I ◽  
Group Ii

Adequate regulatory proteins, growth factors, and hormones in in vitro embryo culture systems are important for improving the quality of embryos to a level similar to that in vivo conditions. The objective of this study was to define the effects of leptin, insulin-like growth factor-1 (IGF-1), and their combination on embryonic development, apoptosis, and expression profiles of a panel of developmentally important genes. Presumptive zygotes (16–18 h post-insemination) were randomly assigned and cultured in control (no supplementation), 5 ng/mL leptin (Group I), 100 ng/mL IGF-1 (Group II), and 5 ng/mL leptin and 100 ng/mL IGF-1 (Group III), all supplemented with 10% FCS on Day 4. On Day 8, the embryos reaching blastocyst stage were randomly either fixed for determination of DNA-fragmented nuclei by using terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) or frozen for real-time relative quantitative RT-PCR analysis. The RT-PCR was performed to assess gene transcripts of glucose transporter-1 (Glut-1), heat shock protein 70.1 (Hsp70.1), interferon tau (IF-tau), insulin-like growth factor II receptor (IGF-IIr), desmosomal glycoprotein desmocollin III (DcIII), and DNA methyltransferase 3a (Dnmt3a). A total of 349, 322, 347, and 360 zygotes were used for the control group and Groups I, II, and III, respectively. Data were analyzed with a randomized complete block design and arcsine square root transformation of the dependent variables consisting of four treatments and six replicates. Cleavage rates were 79.5, 84.2, 87.3, and 82.4% for the control group and Groups I, II, and III, respectively, and only Group II was different from the control (P < 0.05). The percentages of embryos developed beyond the 8–16 cell stage were 44.2, 48.2, 49.0, and 50.7 for the control group and Groups I, II, and III, respectively, and Group III was different from the control (P < 0.05). Percentages of blastocyst development were 26.7, 29.6, 31.5, and 29.8, and the mean blastocyst cell numbers were 96.6, 98.6, 104.4, and 104.1 for the control group and Groups I, II, and III, respectively. The percentage of nuclei with fragmented DNA were 4.2, 3.3, 2.5, and 1.9 for the control group and Groups I, II, and III, respectively. Addition of IGF-1 and/or combination with leptin (Groups II and III) decreased the number of nuclei with fragmented DNA (P < 0.01) as compared to the control group. Although the expression of Glut1, DcIII, and Igf2r did not change among the groups, IF-tau and Dnmt3a were down-regulated in Group II. Hsp70 and IF-tau were up regulated in Group III. Results indicate that addition of IGF-I in culture media improved the cleavage rate; combination with leptin also improved the development rates to 8–16-cell-stage embryos, decreased the TUNEL-positive nuclei, and altered expression of some of the developmentally important genes.

114 Insulin-Like Growth Factor (IGF)2 and IGF2 Receptor (IGF2R) Murine Blastocyst Transcriptional Response after High Gaseous Pressure Exposure at 8-Cell Stage

2018 ◽  
Vol 30 (1) ◽  
pp. 196
Author(s):  
B. S. Becker ◽  
F. J. F. Collares ◽  
A. V. Gonsiorosky ◽  
C. Rodrigues de Freitas ◽  
D. A. Mentz ◽  
...  
Keyword(s):  
Growth Factor ◽  
Internal Control ◽  
Growth And Development ◽  
Paternal Allele ◽  
Control Group ◽  
Insulin Like Growth Factor ◽  
Mus Musculus Domesticus ◽  
Cell Stage ◽  
Imprinted Gene

Insulin-like growth factor 2 (IGF2) is a pleiotropic hormone encoded by an imprinted gene expressed in the paternal allele of mammals, and acts in physiological responses including cell proliferation, differentiation, and development. It is mediated through the IGF1R signalling pathway, whereas the IGF2R, a maternally imprinted gene, acts on lysosomal IGF2 degradation. As imprinted genes, both Igf2 and Igf2r expressions are more susceptible to dysregulation by environmental factors. This study aimed to evaluate the effect of exposure of 8-cell-stage murine embryos to 16 MPa of high gaseous pressure (HGP) on the relative Igf2 and Igf2r mRNA abundance in resulting blastocysts following in vitro culture (IVC). Day-3 embryos were recovered from superovulated Mus musculus domesticus females. Eight-cell embryos were exposed to 16 MPa HGP for either 2 h (P1 group) or 4 h (P2 group), with a Control group not exposed to HGP. Immediately after recovery or HGP exposure, embryos were in vitro-cultured for 48 h in mKSOM medium supplemented with 0.4% BSA at 37.5°C, 5% CO2, 5% O2, 90% N2, and saturated humidity. Resulting blastocysts were collected in pools of 10 and stored at –80°C, pending analysis. Following total mRNA extraction, cDNA syntesis and RT-qPCR were performed according to manufacturers. Values were normalized to the internal control Ppia gene. Relative gene expression was calculated using the 2−ΔΔ Ct approach. Blastocyst rates after IVC were compared by the Chi-squared test (P < 0.05), with relative Igf2 and Igf2r expression data and Igf:Igf2r ratio analysed by ANOVA, after log-transformation when needed, with pairwise comparisons done by the Tukey test (P < 0.05). No differences in blastocyst rates after IVC were observed among groups (Control: 94.2%; P1: 95.4%; P2: 94.1%). However, the Igf2 mRNA relative abundances in blastocysts were 6.3- and 4.2-fold lower in P1 (P < 0.01) and P2 (P = 0.07) than in the Control group, respectively. Likewise, the Igf2r relative transcription levels were 6.6- and 2.2-fold down-regulated in blastocysts from the P1 (P < 0.001) and P2 (P < 0.01) groups, respectively, when compared with controls. Although the relative expression for both genes followed a down-regulation pattern in blastocysts exposed to HGP at the 8-cell stage, the Igf2:Igf2r ratio was 1.9-fold lower in blastocysts in the P2 group (P < 0.05) than Controls, which was similar to the P1 group, indicating a potential stress adaptation response for embryo growth and development after exposure to HGP in the P1 group. It is known that cells under certain conditions of stress may halter growth and development as a response to initiate cellular events to maintain viability. Results from this study appear to translate such response process to HGP in both experimental groups. However, as embryo development and the Igf2:Igf2r ratio in embryos were similar between the Control and the P1 group, exposure to 16 MPa HGP for 2 h at the 8-cell-stage embryo does not seem to affect cell signalling to growth and proliferation up to the blastocyst stage.

scholarly journals miR-139 Functions as An Antioncomir to Repress Glioma Progression Through Targeting IGF-1 R, AMY-1, and PGC-1β

2016 ◽  
Vol 16 (4) ◽  
pp. 497-511 ◽  
Author(s):  
Hong Wang ◽  
Xi Yan ◽  
Li-Ya Ji ◽  
Xi-Tuan Ji ◽  
Ping Wang ◽  
...  
Keyword(s):  
Growth Factor ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Epigenetic Modification ◽  
Negative Control ◽  
Peroxisome Proliferator ◽  
Insulin Like Growth Factor ◽  
Peroxisome Proliferator Activated Receptor

Gliomas are the most common primary malignant brain tumor with poor prognosis, characterized by a highly heterogeneous cell population, extensive proliferation, and migration. A lot of molecular mechanisms regulate gliomas development and invasion, including abnormal expression of oncogenes and variation of epigenetic modification. MicroRNAs could affect cell growth and functions. Several reports have demonstrated that miR-139 plays multifunctions in kinds of solid tumors through different pathways. However, the antitumor mechanisms of this miR-139 are not unveiled in detail. In this study, we not only validated the low expression level of miR-139 in glioma tissues and cell lines but also detected the effect of miR-139 on modulating gliomas proliferation and invasion both in vitro and in vivo. We identified insulin-like growth factor 1 receptor, associate of Myc 1, and peroxisome proliferator-activated receptor γ coactivator 1β as direct targets of miR-139 and the levels of them were all inversely correlated with miR-139 in gliomas. Insulin like growth factor 1 receptor promoted gliomas invasion through Akt signaling and increased proliferation in the peroxisome proliferator-activated receptor γ coactivator 1β-dependent way. Associate of Myc 1 also facilitated gliomas progression by activating c-Myc pathway. Overexpression of the target genes could retrieve the antitumor function of miR-139, respectively, in different degrees. The nude mice transplantation tumor experiment displayed that glioma cells stably expressed miR-139 growth much slower in vivo than the negative control cells. Taken together, these findings suggested miR-139 acted as a favorable factor against gliomas progression and uncovered a novel regulatory mechanism, which may provide a new evidenced prognostic marker and therapeutic target for gliomas.

200 STAGE-SPECIFIC EXPRESSION PATTERNS OF THE INSULIN-LIKE GROWTH FACTOR 1 RECEPTOR DURING BOVINE PRE-IMPLANTATION EMBRYONIC DEVELOPMENT

2015 ◽  
Vol 27 (1) ◽  
pp. 191 ◽  
Author(s):  
F. Poppicht ◽  
H. Stinshoff ◽  
C. Wrenzycki
Keyword(s):  
Growth Factor ◽  
Embryonic Development ◽  
Protein Expression ◽  
Mrna Expression ◽  
Early Embryonic Development ◽  
Insulin Like Growth Factor ◽  
Bovine Embryos ◽  
Cell Stage ◽  
Igf1r Expression

Insulin-like growth factor 1 (IGF1) is a key regulator in early embryonic development, influencing physiological processes and stimulating growth and development (Fowden et al. 2003). Supplementing IGF1 during in vitro culture of bovine embryos improved cleavage and developmental rates while it reduced apoptosis (Byrne et al. 2002). The signal transduction of IGF1 is performed by its binding to the insulin-like growth factor 1 receptor (IGF1R). At the mRNA level, IGF1R is expressed throughout pre-implantation embryonic development and was identified as a potential marker of good quality embryos (Yaseen et al. 2001). However, information on protein level is rare. Therefore, protein expression of the IGF1R during early embryonic development in vitro was analysed in the present study by immunofluorescence staining. Furthermore, the mRNA expression of the IGF1R was investigated by RT-qPCR. In vitro derived embryos of different stages (2-cell, 4-cell, 8-cell, 16-cell stage, morula, blastocyst, and expanded blastocyst) were either directly subjected to immunofluorescence staining or frozen at –80°C for use in RT-qPCR. Staining was performed with a peptide antibody against two peptide sequences of the bovine IGF1R α unit, which was specifically produced. Pixel intensity of immunofluorescence was measured and a mean grey value was calculated using the cellsens® software (Olympus, Hamburg, Germany). Data were analysed by one-way ANOVA followed by a Tukey's test using SigmaStat 3.5 Software (Systat Software GmbH, Erkrath, Germany). The detection of the IGF1R mRNA and protein was possible in all stages of embryonic development beginning at the 2-cell stage up to the expanded blastocyst. The maximal mRNA expression could be observed in 2- and 4-cell embryos. It significantly decreased to the 8-cell stage, followed by an increase up to the expanded blastocyst. The IGF1R protein was mainly localised in the plasma membrane of single blastomeres and also weakly in the cytoplasm. Mean grey values are highest in the 2-cell stage, showing a significant decline up to the 16-cell stage and an increase again until the expanded blastocyst. The mRNA and protein expression showed similar patterns during early embryonic development. IGF1R expression started to increase at the 8-cell stage (mRNA) and 16-cell stage (protein) indicating a link to the maternal-embryonic transition. For the first time, these results show that in bovine embryos, the IGF1R expression is related to the activation of the embryonic genome. We gratefully acknowledge the financial support of the H. Wilhelm Schaumann Foundation (Hamburg, Germany).

scholarly journals 48EFFECT OF INSULIN-LIKE GROWTH FACTOR-1 SUPPLEMENT TO NCSU-23 MEDIUM ON PREIMPLANTATION DEVELOPMENT OF PORCINE EMBRYOS DERIVED FROM IN VITRO FERTILIZATION AND SOMATIC CELL NUCLEAR TRANSFER

2004 ◽  
Vol 16 (2) ◽  
pp. 146
Author(s):  
S. Kim ◽  
D.H. Nam ◽  
Y.W. Jung ◽  
H.S. Kim ◽  
S.H. Lee ◽  
...  
Keyword(s):  
Growth Factor ◽  
Nuclear Transfer ◽  
Cell Number ◽  
Total Cell ◽  
Insulin Like Growth Factor ◽  
Total Cell Number ◽  
Cell Stage ◽  
Vitro Fertilization ◽  
Igf I

The developmental potential of in vitro production of embryos is affected by various factors, including the culture system, oocyte quality, the presence of serum, and embryo paracrine and autocrine growth factors. Insulin-like growth factor is a good stimulator of oocyte maturation and embryo development. The present study investigated the effect of insulin-like growth factor-I (IGF-I) supplement on the preimplantation development of porcine embryos derived from in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT). Developmental competence was evaluated by monitoring the numbers of 2-cell embryos and blastocysts at Days 2 and 7, respectively. The number of total cells and inner cell mass (ICM) cells in blastocysts were counted after differential staining at Day 7. All data were analyzed by ANOVA using a Generalized Linear Model (SAS). In Experiment 1, a total of 2,462 in vitro-matured oocytes (527, 458, 498, 481 and 498, respectively) were inseminated with frozen-thawed boar semen and subsequently cultured in North Carolina State University (NCSU)-23 medium supplemented with various concentrations of IGF-1 (0, 1, 10, 50 and 100ngmL−1). As a result, significant model effects on the development to the 2-cell stage (P=0.033) and to the blastocyst stage (P=0.0067) were found, and more blastocysts (16.9, 16.6, 17.5, 21.8 and 14.7 %, respectively) were obtained in medium supplemented with 50ngmL−1 of IGF-I. Moreover, increase in the total cell number (56.5, 53.2, 74.0, 76.4 and 58.4) and ICM (6.6, 5.8, 9.3, 9.4 and 6.1) cells was observed in IVF embryos cultured in NCSU-23 medium supplemented with 50ngmL−1 IGF-1. In Experiment 2, porcine cloned embryos were produced by our standard protocol using fetal fibroblasts as donor cells (Hyun SH et al., 2003 Theriogenology 59, 1641–1649) and cultured in NCSU-23 supplemented with the same concentration of IGF-1 as Experiment 1. As a result, a total of 501 reconstructed oocytes (99, 98, 102, 99 and 96, respectively) were cultured and significant model effects on the development to the 2-cell stage (P=0.0179) were found. More blastocysts (10.5, 11.2, 11.8, 20.8 and 10.1%) were produced when embryos were cultured in NCSU-23 medium supplemented with 50ngmL−1, even though no statistical significance was found (P=0.1182). Increases in the total cell number (42.7, 46.0, 45.9, 51.1 and 38.2) and ICM cells (3.8, 3.8, 5.6, 6.6 and 4.8, respectively) were observed in cloned embryos cultured in NCSU-23 medium supplemented with 50ngmL−1 of IGF-I. In conclusion, the present study demonstrated that IGF-1 at the concentration of 50ngmL−1 improves the development of preimplantion embryos derived from IVF and SCNT. This study was supported by the Advanced Backbone IT Technology Development (IMT 2000-C1-1).

scholarly journals Influence of Insulin-like Growth Factor I (IGF-I) on the survival and the in vitro development of caprine preantral follicles

2014 ◽  
Vol 34 (10) ◽  
pp. 1037-1044 ◽  
Author(s):  
Sanely L. Costa ◽  
Eduardo P. Costa ◽  
Emílio C.M. Pereira ◽  
Laércio A. Benjamin ◽  
Marcelo T. Rodrigues ◽  
...  
Keyword(s):  
Growth Factor ◽  
Culture Medium ◽  
Insulin Like Growth Factor ◽  
Preantral Follicles ◽  
Factor I ◽  
Transmission Electron ◽  
Igf I ◽  
Growth Factor I ◽  
Vitro Development

The aim of this study was to investigate the effects of the insulin-like growth factor -I (IGF-I) on survival, activation (transition from primordial to primary follicles) and growth of caprine preantral follicles cultured in vitro. Fragments of ovarian cortex were cultured for one and seven days in the absence or presence of IGF-I (0, 50 and 100ng/ml). The non-cultured and cultured tissues were processed and analyzed by histology and transmission electron microscopy. The culture for one day in a medium with 100ng/ml of IGF-I showed 86.7% of morphologically normal follicles. These results were similar (P>0.05) to the percentage of normal follicles found in the control (96.7%). It was also found that this medium increased the percentage of follicular activation (developing follicles) with one day of culture. The oocyte and follicular diameters remained similar to the control by culturing for one day in a medium containing 100ng/ml of IGF-I. The ultrastructural analysis did not confirm the integrity of the follicular fragments in a medium containing IGF-I (100ng/ml) after one and seven days of culture. In conclusion, this study demonstrated that the addition of 100 ng/ml of IGF-I in the culture medium enables the development of preantral follicles of goats with one day of culture. However, it is not sufficient to maintain the follicular integrity and the follicular survival rate after seven days of culture.

189 EFFECT OF PROGESTERONE AND EPIDERMAL GROWTH FACTOR ON IN VITRO-PRODUCED EIGHT-CELL BOVINE EMBRYOS IN A SERUM-FREE CULTURE MEDIUM

2007 ◽  
Vol 19 (1) ◽  
pp. 211 ◽  
Author(s):  
B. Merlo ◽  
E. Iacono ◽  
G. Mari
Keyword(s):  
Growth Factor ◽  
Embryo Development ◽  
Culture Medium ◽  
Bovine Embryo ◽  
Bovine Embryos ◽  
Cell Stage ◽  
Serum Free ◽  
Epidermal Growth ◽  
Blastocyst Rate

The role of progesterone (P4) and epidermal growth factor (EGF) in early bovine embryo development is still not clear. P4 has been administered at different times of embryo development, and a direct effect on IVF-derived bovine 8-cell embryos has been noted even if there was an interference due to the P4 vehicle (Ferguson et al. 2005 Reprod. Fertil. Dev. 17, 219 abst). EGF has been added to the culture medium from the presumptive zygote stage at different concentrations, resulting in improved blastocyst rates compared to that in control medium (Mtango et al. 2003 Theriogenology 59, 1393–1402; Sirisathien et al. 2003 Anim. Reprod. Sci. 77, 21–32), and gave results similar to those with 5% or 10% FCS (Palasz et al. 2000 Anim. Reprod. Sci. 58, 229–240). The objective if this experiment was to determine the effect of P4 and EGF on development of in vitro-produced bovine embryos when administered alone or in combination at the 8-cell stage in the absence of serum. In vitro-produced bovine 8-cell embryos were randomly allotted to treatments: (1) control, SOFaaBSA medium (BSA, 16 mg mL−1; n = 198); (2) P4, SOFaaBSA + P4 (15 ng mL−1 in ethanol; n = 198); (3) EGF, SOFaaBSA + EGF (25 ng mL−1; n = 200); (4) P4 + EGF, SOFaaBSA + P4 (15 ng mL−1 in ethanol) + EGF (25 ng mL−1; n = 201); and (5) FBS, SOFaaBSA + FBS (5%; n = 197). In order to minimize the toxic effect of ethanol, it was allowed to evaporate from the culture dish and then medium was added. All in vitro procedures were carried out at 38.5°C in a humidified atmosphere of 5% CO2 in air; presumptive zygotes were cultured in SOFaaBSA until 8-cell stage. Embryo development was evaluated on Day 6 and on Day 8 after IVF (Day 0), and rates calculated from 8-cell embryos. The study was done in 4 replicates and chi-square test was used for statistical analysis (Statistica for Windows; Stat Soft Inc., Tulsa, OK, USA); significance was assessed at P &lt; 0.05. Results are reported in Table 1. No differences were found in the number of morulae between P4 and control, between P4 + EGF and FBS, and between P4 + EGF and EGF (P &gt; 0.05), whereas the combination P4 + EGF was better than P4 alone (P &lt; 0.05). Blastocyst rate was not different (P &gt; 0.05) among EGF, P4 + EGF, and FBS groups. P4 achieved an higher (P &lt; 0.05) blastocyst rate than control but it was lower (P &lt; 0.05) than that of P4 + EGF or FBS. In conclusion, P4 alone improves embryo development from the 8-cell embryo to the blastocyst stage in a serum-free culture system, and EGF alone achieves a blastocyst rate not significantly different from that of FBS; furthermore, the combination of P4 and EGF can be considered the most suitable as an alternative to FBS because similar results were obtained in terms of both morulae and blastocysts. Table 1.Eight-cell bovine embryo development in SOFaaBSA medium in presence of P4, EGF, P4+EGF, or FBS

The role of insulin-like growth factor II and its receptor in mouse preimplantation development

2003 ◽  
Vol 15 (1) ◽  
pp. 37 ◽  
Author(s):  
M. Pantaleon ◽  
H. Jericho ◽  
G. Rabnott ◽  
P. L. Kaye
Keyword(s):  
Growth Factor ◽  
Growth Regulation ◽  
Negative Regulator ◽  
Insulin Like Growth Factor ◽  
Mouse Development ◽  
Cleavage Rate ◽  
Cell Stage ◽  
Factor Ii

Insulin-like growth factor II (IGF-II) and its receptor, the IGF-II/mannose-6-phosphate (IGF-II/M6P) receptor, are first expressed from the zygotic genome at the two-cell stage of mouse development. However, their role is not clearly defined. Insulin-like growth factor II is believed to mediate growth through the heterologous type 1 IGF and insulin receptors, whereas the IGF-II/M6P receptor is believed to act as a negative regulator of somatic growth by limiting the availability of excess levels of IGF-II. These studies demonstrate that IGF-II does have a role in growth regulation in the early embryo through the IGF-II/M6P receptor. Insulin-like growth factor II stimulated cleavage rate in two-cell embryos in vitro. Moreover, this receptor is required for the glycaemic response of two-cell embryos to IGF-II and for normal progression of early embryos to the blastocyst stage. Improved development of embryos in crowded culture supports the concept of an endogenous embryonic paracrine activity that enhances cell proliferation. These responses indicate that the IGF-II/M6P receptor is functional and likely to participate in such a regulatory circuit. The functional role of IGF-II and its receptor is discussed with reference to regulation of early development.

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