Nonspecies-specific effects of mouse oviducts on the development of bovine IVM/IVF embryos by a serum free co-culture

Activin/nodal signaling switches the terminal fate of human embryonic stem cell-derived trophoblasts

Human embryonic stem cells (hESCs) have been routinely treated with bone morphogenetic protein and/or inhibitors of activin/nodal signaling to obtain cells that express trophoblast markers. Trophoblasts can terminally differentiate to either extravillous trophoblasts or syncytiotrophoblasts. The signaling pathways that govern the terminal fate of these trophoblasts are not understood. We show that activin/nodal signaling switches the terminal fate of these hESC-derived trophoblasts. Inhibition of activin/nodal signaling leads to formation of extravillous trophoblast, whereas loss of activin/nodal inhibition leads to the formation of syncytiotrophoblasts. Also, the ability of hESCs to form bona fide trophoblasts has been intensely debated. We have examined hESC-derived trophoblasts in the light of stringent criteria that were proposed recently, such as hypomethylation of the ELF5-2b promoter region and down-regulation of HLA class I antigens. We report that trophoblasts that possess these properties can indeed be obtained from hESCs.

Oviductal and endometrial mRNA expression of implantation candidate biomarkers during early pregnancy in rabbit

Prenatal losses are a complex problem. Pregnancy requires orchestrated communication between the embryo and the uterus that includes secretions from the embryo to signal pregnancy recognition and secretion and remodelling from the uterine epithelium. Most of these losses are characterized by asynchronization between embryo and uterus. To better understand possible causes, an analysis was conducted of gene expression of a set of transcripts related to maternal recognition and establishment of rabbit pregnancy (uteroglobin,SCGB1A1; integrin α1,ITGA1; interferon-γ,IFNG; vascular endothelial growth factor,VEGF) in oviduct and uterine tissue at 16, 72 or 144 h post-ovulation and insemination. In the oviduct tissue, a significant decrease in the level ofSCGB1A1mRNA expression was observed from 144 h post-ovulation. In the case ofITGA1, the transcript abundance was initially lower, but mRNA expression increased significantly at 72 and 144 h post-ovulation. ForIFNG, a huge decrease was observed from 16 to 72 h post-ovulation. Finally, no significant differences were observed in theVEGFtranscript. For the endometrium, the results showed a significant decline in the level ofSCGB1A1mRNA expression from 16 to 144 h post-ovulation induction. The highest levels ofITGA1transcript were detected at 144 h, followed by the 16 h group and lower at 72 h post-ovulation. ForIFNGthere were no significant differences among post-ovulation induction times. Finally, it was possible to observe thatVEGFmRNA abundance was present at low levels at 16 h post-ovulation and remained low at 72 h, but increased at 144 h. The functional significance of these observations may provide new insights into the maternal role in prenatal losses.

Interação do Mycoplasma bovigenitalium com células do cumulus in vitro após o período de maturação oocitária bovina

O Mycoplasma é considerado cosmopolita, podendo ser disseminado através do comércio internacional de animais, sêmen industrializado e de produtos de transferência de embriões. A expansão de células do cumulus é utilizada como parâmetro de avaliação de oócitos bovinos cultivados in vitro e suas alterações morfológicas são representativas. O objetivo deste trabalho foi avaliar a interação do Mycoplasma bovigenitalium, exposto experimentalmente à cultura primária de célula do cumulus, após o período de maturação. Complexos oócitos cumulus (COCs) obtidos através de punção folicular de ovários bovinos, provenientes de abatedouro, foram divididos em dois grupos para serem maturados durante 24h em meio de maturação (TCM199 + hormônios) em estufa a 38º C, 5% de CO2, 95% de umidade. Posteriormente, os oócitos foram retirados das placas, permanecendo somente com as células do cumulus aderidas. Com o monoestrato celular formado, um grupo foi infectado com 30 mL de M. bovigenitalium, replicado em meio Hayflick modificado a 37º C em estufa de microaerofilia, enquanto o outro foi mantido como controle. Os resultados mostraram que, com 24h de exposição ao patógeno, as culturas apresentaram um pequeno número de células arredondadas e granulosas, quando comparadas as dos controles. Esse efeito persistiu até o sétimo dia, onde se iniciou um processo de descolamento das células. Pode-se concluir que uma contaminação por micoplasma pode ser imperceptível às manipulações da FIV, pois células infectadas por esse grupo de bactérias não apresentam turvações no meio de cultura e, quando não lisam a célula hospedeira, tornam mais suscetível ao ambiente e outros agentes infecciosos.

Oviductal, endometrial and embryonic gene expression patterns as molecular clues for pregnancy establishment

In higher animals, the beginning of new life and transfer of genetic material to the next generation occurs in the oviduct when two distinct gametes cells unite resulting in the formation of a zygote. The zygote then undergoes serial developmental processes in the oviduct and enters into the uterus where it faces challenges and scrutiny from the endometrial ecosystem. Thus, embryos that are able to establish an appropriate embryo-maternal dialogue are capable of developing to term whereas the incompetent ones can perish any time during the gestation period. Although several lines of evidences indicated that pregnancy loss is a multi-factorial phenomenon, the biochemical composition of the embryo and maternal environment are the main players to determine pregnancy outcome. Indeed, expression patterns of the genes are the driving forces that induce biochemical composition changes in embryo, oviduct and uterine environment. Thus, examining the molecular signals that are associated with oviductal or endometrial receptivity and embryo implantation is essential for establishing strategies to improve pregnancy success. Therefore, this review focuses on the contribution of oviduct and its transcriptome profile on early stage embryo development and the impact of endometrium and its transcriptome changes on peri and post embryo implantation. In addition, this paper integrates established facts about hormonal and molecular signatures associated with endometrial receptivity. Finally, the blastocyst and pre-conception endometrial gene expression profiles have been discussed in relation to the pregnancy outcome to highlight the potentials of blastocyst and pre-transfer endometrial transcriptome profile approach for selecting appropriate recipient and developmentally competent embryo.

Effects of retinoic acid on maturation of immature mouse oocytes in the presence and absence of a granulosa cell co-culture system

PURPOSE

Evaluation of the all-trans retinoic acid (t-RA) effects on in vitro maturation (IVM) and in vitro fertilization (IVF) of immature mouse oocytes in the presence and absence of granulosa cell monolayer.

METHODS

Denuded oocytes isolated from mice ovaries and matured in IVM medium alone (Control I), IVM medium in the presence of granulosa cells (Control II), IVM medium with t-RA (Experimental I) and IVM medium simultaneously with t-RA and granulosa cells (Experimental II). After 24 h, matured oocytes were fertilized in T6 medium and their development was followed until the blastocyst stage. Metaphase II oocytes ploidy were evaluated by chromosome counting.

RESULTS

The t-RA group compared to the control groups showed no obvious abnormalities. Additionally maturation and embryo development rates significantly increased in the t-RA treated granulosa cell co-culture system.

CONCLUSIONS

In conclusion, association of t-RA with granulosa cell co-culture during in vitro maturation increases meiosis resumption, formation of metaphase II oocytes, as well as 2-cell and blastocyst stage embryos.

Inhibitory effect of phosphate on in vitro development of 2-cell rat embryos is overcome by a factor(s) in oviductal extracts

It has been found that inorganic phosphate (P) at concentrations as low as 10 microM markedly inhibits in vitro development of early rat embryos at the 1-cell or 2-cell stage to the blastocyst stage, although P is present at concentrations of 0.37-1.19 mM in oviductal fluid, in which the development of early embryos occurs. We show here that fractions (PTF, 50-250 microg/ml) of rat oviductal extracts (OVEs) passed through a Blue CL6B affinity column have the ability to overcome the inhibitory effects of P on the development of 2-cell rat embryos in a dose-dependent manner, whereas 250 microg/ml OVE or 250 microg/ml of the bound fractions (BF) induced degenerative changes in the embryos at the 2-cell stage. Moreover, PTF at concentrations of >/=100 microg/ml stimulated the hatching of blastocysts both in medium with and without P, although none of the blastocysts in medium without PTF hatched from their zona pellucida.

Effect of oviductal cell co-culture on cleavage and development of goat IVF embryos

The present study was undertaken with the aim to study the role of isologous and heterologous (buffalo) oviductal cell to co-culture on in vitro development of goat embryos. The oocytes were collected by puncturing the goat ovaries obtained from slaughterhouse. The oocyte recovery rate per ovary was 3.0. The media used for oocyte maturation and embryo development was TCM-199 + 10 percent buffalo estrus serum. A total of 79.8 percent oocytes got matured out of 1056 oocytes. The oocytes were inseminated with epididymal buck spermatozoa capacitated in Brackett and Oliphant media. In group I without oviductal cells co-culture only 13.6 percent matured oocytes cleaved and 3.3 and 0.0 percent reached the morula and blastocyst stage. In group II and III having goat and buffalo oviductal cells the cleavage was 57.6 and 59.2 percent respectively. The percentage of morula, blastocyst and those embryos arrested between 2-16 cells were 26.3, 10.2, 63.5 and 26.6, 8.9 and 64.5 in goat and buffalo oviductal cell groups. The results indicated that the oviductal cell co-culture had a marked effect on cleavage and development of goat IVF embryos. Buffalo oviductal cells can be used well for goat embryo development.