Expression Pattern of E- and P-Cadherin in Mouse Embryos and Uteri during the Periimplantation Period: (implantation/mouse embryo/cell adhesion molecules E-cadherin/P-cadherin).

Periimplantation mouse embryos and uterine tissues were examined by means of immunohistochemistry for their expression of the Ca dependent cell-cell adhesion molecules, E- and P-cadherin. E-cadherin was detected in all embryonic cells during periimplantation stages, and also detected in the uterine epithelium. When blastocysts attached to the uterine epithelium, E-cadherin was detected at implantation sites between the mural trophectoderm and the uterine epithelium on 5 day of pregnancy. P-cadherin was first detected in the mural trophectoderm on 4.5-day blastocysts, and then detected in the ectoplacental cone, giant cells and visceral endoderm from 5.5 day. P-cadherin was also detected in the maternal uterine decidual cells from 5.5 day. After degeneration of uterine epithelial cells, giant cells make direct contact with uterine decidual cells, and P-cadherin was detected at contact sites between these cells. Thus, the complicated process of implantation seems to be supported by temporal and spatial expression of the multiple classes of cadherins.