Perlecan and Syndecan-4 in Uterine Tissues during the Early Pregnancy in Mice

Problem: During early pregnancy in mice, there is recruitment of specific immune cells, remodeling of the endometrium, cell differentiation and synthesis of new molecules. Method of study: Immunohistochemistry was used to determine the distribution of perlecan and syndecan‐4 in the uteri before and after embryo implantation. Results: During pre‐implantation, perlecan was identified in basement membranes and extracellular spaces of the endometrial stroma. In contrast, expression of syndecan‐4 was quite weak. In the peri‐implantation period, perlecan remained in the basement membranes, and it was no longer observed in the stroma and it was identified in the embryonic cells. On day 4 of pregnancy, syndecan‐4 increased in the fibroblasts of the subepithelial stroma. After implantation, syndecan‐4 was pronounced in pre‐decidual and mature decidual cells. Conclusions: The coordinate balance between the pre‐ and post‐implantation periods suggests a role of these two molecules in the adaptive modification of the uterine microenvironment to receive and implant the embryo.