Adaptive mechanisms controlling uterine spiral artery remodeling during the establishment of pregnancy

Implantation of the embryo into the uterus triggers the initiation of hemochorial placentation. The hemochorial placenta facilitates the acquisition of maternal resources required for embryo/fetal growth. Uterine spiral arteries form the nutrient supply line for the placenta and fetus. This vascular conduit undergoes gestation stage-specific remodeling directed by maternal natural killer cells and embryo-derived invasive trophoblast lineages. The placentation site, including remodeling of the uterine spiral arteries, is shaped by environmental challenges. In this review, we discuss the cellular participants controlling pregnancy-dependent uterine spiral artery remodeling and mechanisms responsible for their development and function. © 2014 UBC Press

Regulatory pathways controlling the endovascular invasive trophoblast cell lineage

Hemochorial placentation is characterized by trophoblast-directed uterine spiral artery remodeling. The rat and human both possess hemochorial placentation and exhibit remarkable similarities regarding the depth of trophoblast invasion and the extent of uterine vascular modification. In vitro and in vivo research methodologies have been established using the rat as an animal model to investigate the extravillous/invasive trophoblast lineage. With these research approaches, two signaling pathways controlling the differentiation and invasion of the trophoblast cell lineage have been identified: i) hypoxia/hypoxia inducible factor and ii) phosphatidylinositol 3-kinase/AKT/Fos like antigen 1. Dissection of these pathways has facilitated identification of fundamental regulators of the invasive trophoblast cell lineage. © 2012 by the Society for Reproduction and Development

Soybean Milk–Based Extender for Cryopreservation of Buck Spermatozoa

The aim of this study was to investigate incorporating whole soybean milk instead of the traditional egg yolk in goat semen extender. The semen ejaculates were collected from three fertile bucks, aged 2–3 years using artificial vagina. Collected semen was divided into 6 parts; the first was diluted with Tris–egg yolk extender (TEY) saved as control, while the others were diluted with Tris– soybean milk extender (TSM) at levels of 5, 10, 15, 20 and 25%. Pooled ejaculates were further processed for freezing using 0.25 ml French straws. Diluted semen at a rate of 1:4 was placed into a refrigerator at 5°C for 4 h as equilibration period. At the end of equilibration period, extended semen was packaged in straws and stored at –196°C. Then after, frozen semen was thawed by dipping the straws into a water bath at 37°C for 30 seconds. Percentages of sperm motility, live spermatozoa, sperm abnormalities and recovery rate were determined. The results revealed that there were significant differences (P<0.05) in buck sperm characteristics (percentages of sperm motility, live spermatozoa, sperm abnormalities and plasma membrane and acrosome integrity) among post–dilution, post equilibration and post thawing processes. Addition of 15% of soybean milk led to a significant (P<0.05) improvement of sperm motility, live spermatozoa, sperm abnormalities and plasma membrane and acrosome integrity of buck spermatozoa during different stages of cryopreservation compared to control, while the lowest values were recorded at a level of 25% soybean milk extender. On the basis of our results, we concluded that soybean milk–based extender at the rate of 15% of soybean milk has the potential to maintain buck sperm quality after freezing –thawing process compared with cryopreservation in a traditional protection extender (egg yolk)

Effect of Glutathione on Cryopreservation of Buck Spermatozoa

The aim of this study was to assay supplementation of glutathione into the traditional egg yolk extender for cryopreservation of goat spermatozoa. Semen ejaculates were collected from three fertile baladie bucks, aged 2–3 years using artificial vagina. Collected semen was divided into four aliquots; the first was diluted with Tris–egg yolk extender without any supplementation (Control), while the others were diluted with Tris–egg yolk extender supplemented with glutathione at levels of 2, 4 and 6 mM. Semen diluted at a rate of 1:4 and placed into a refrigerator at 5°C for 4 h to equilibrate. At the end of equilibration period, extended semen was packaged in liquid 0.25 ml French straws and stored in liquid nitrogen at –196°C. Thereafter, frozen semen was thawed by dipping the straws into a water bath at 37°C for 30 seconds. Percentages of progressive motility, live sperm, sperm abnormalities, plasma membrane and acrosome integrity were evaluated post dilution, equilibration period and post–thawing of spermatozoa. The results revealed that there were significant differences (P<0.05) of various sperm characteristics (percentages of sperm motility, live spermatozoa and sperm abnormalities, plasma membrane and acrosome integrity) in post–diluted, post equilibration and post thawing of goat semen. Treatment supplemented with 6 mM of glutathione led to significantly (P<0.05) improve the percentages of progressive motility, live spermatozoa and sperm abnormalities, plasma membrane and acrosome integrity of buck spermatozoa during different stages of cryopreservation compared to control and other levels of glutathione addition. While the extender supplanted with 2 mM glutathione was recorded the lowest value of semen parameters approximately. In conclusion, supplementation of Tris–egg yolk extender used for buck semen extender during freezing–thawing process with 6 mM of glutathione improves percentages of progressive motility, live spermatozoa, sperm abnormalities, plasma membrane and acrosome integrity of frozen–thawed buck spermatozoa

FGF4-dependent stem cells derived from rat blastocysts differentiate along the trophoblast lineage

AbstractDifferentiated trophoblast cell lineages arise from trophoblast stem (TS) cells. To date such a stem cell population has only been established in the mouse. The objective of this investigation was to establish TS cell populations from rat blastocysts. Blastocysts were cultured individually on a feeder layer of rat embryonic fibroblasts (REFs) in fibroblast growth factor-4 (FGF4) and heparin supplemented culture medium. Once cell colonies were established REF feeder layers could be replaced with REF conditioned medium. The blastocyst-derived cell lines, in either proliferative or differentiated states, did not express genes indicative of ICM-derived tissues. In the proliferative state the cells expressed established stem cell-associated markers of TS cells. Cells ceased proliferation and differentiated when FGF4, heparin, and REF conditioned medium were removed. Differentiation was characterized by a decline of stem cell-associated marker gene expression, the appearance of large polyploid cells (trophoblast giant cells), and the expression of trophoblast differentiation-associated genes. Collectively, the data indicate that the rat blastocyst-derived cell lines not only possess many features characteristic of mouse TS cells but also possess some distinct properties. These rat TS cell lines represent valuable new in vitro models for analyses of mechanisms controlling TS cell renewal and differentiation