Localization of C-Fos-Induced Growth Factor (Figf) mRNA Expression in the Mouse Uterus during Implantation

The purpose of this study was to characterize the localization of Figf mRNA in the mouse uterus during embryo implantation. Strong Figf mRNA hybridization signals were seen in the primary decidual zone just after the onset of implantation from Days 4.5–6.5. On Day 7.5, this expression continued around the concept us, but in addition we observed high expression of Figf mRNA in the endothelial cells that line the forming vascular sinusoids in the lateral me some trial decidua. Interestingly, on Days 8.5 this high expression continued in the endothelial cells of sinusoids in the lateral me some trial decidual tissue but not in the decidual cells surrounding the concept us. As implantation and placental development finished, Figf mRNA expression remained in the endothelial cells of the sinusoids and spiral arterioles of the decidua basalis. Interestingly, Flt4 mRNA was localized to the endothelial cells lining the sinusoids that form during implantation. Since the endothelial cells of the me some trial sinusoids exhibit a high level of proliferation, we speculate that FIGF-FLT4 signaling may play a role in their formation and function during implantation. This work will provide a basis for further research on the potential role of FIGF-FLT4 signaling in endometrial angiogenesis during implantation in mice.