Structure of the Plasma Membrane of Uterine Epithelial Cells in Blastocyst Attachment: a Review

Abstract

Changes in the molecular organization of the plasma membrane of uterine epithelial cells during early pregnancy and, in particular, at the attachment period are reviewed. The review focuses on attachment in rodents but other species are also considered. Alterations in protein content and type, as determined with electrophoretic and freeze-fracture techniques, and an increase in tight junction complexity occur in several species. Ultrastructural histochemistry shows that glycocalyx carbohydrates of different species both increase and decrease depending on the type of carbohydrate. Changes in membrane cholesterol content also occur and recent studies showing major reorganization of the actin-containing membrane skeleton are reviewed to show the dynamism of this plasma membrane during the period of uterine receptivity for attachment of the blastocyst.