The Complex Structure of the Mouse Placental Labyrinth Revealed by Double Immunofluorescence Labeling of Slc2a1 and Gjb2

The placenta is a feto-maternal interface during pregnancy. The mouse placenta consists of three major zones: the maternal decidual zone, the junctional zone, and the inner labyrinth zone. The labyrinth zone, which has the most complex structure of the three, includes maternal vascular sinusoids and fetal blood vessels, where the exchange of oxygen and nutrients occurs. Fetal vessels are separated from maternal blood by the blood-placental barrier, which is formed by a single layer of mononuclear trophoblast cells (layer I), a double layer of syncytiotrophoblast cells (layer II and III), and fetal vascular endothelial cells.