Notch 1 signaling pathway effect on implantation competency

ObjectiveTo investigate the relationship between the Notch 1 signaling pathway and the embryo implantation rate.DesignMouse embryos were cultured in vitro, and implantation competency was quantified.SettingTertiary fertility center of a university teaching hospital.Animal(s)Outbred ICR strain mouse embryos.Intervention(s)The expression of Notch 1 was altered by adding a γ-secretase inhibitor to the culture medium. We quantified the consequent effect on embryo implantation.Main Outcome Measure(s)We measured the messenger RNA level of Notch 1 gene at different embryonic stages, embryo implantation rate under different culture conditions, the amount of Notch 1, and related implantation competency.Result(s)Quantitative polymerase chain reaction showed that the expression of Notch 1 increased during the implantation window. Adding γ-secretase inhibitor in the culture medium decreased the percentage of blastocysts in a dose-dependent manner. A Matrigel invasion assay showed that the competency of implantation required adequate expression of Notch 1 intracellular domain.Conclusion(s)Expression of Notch 1 at the proper time is required for the competency of embryo implantation; this effect is mediated through regulation of Notch 1 intracellular domain expression.