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

1992 ◽  
Vol 4 (6) ◽  
pp. 633 ◽  
Author(s):  
CR Murphy

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.

1985 ◽  
Vol 78 (1) ◽  
pp. 163-172
Author(s):  
C.R. Murphy ◽  
B. Martin

Freeze-fracture cytochemistry with digitonin has been used to examine the cholesterol content of the plasma membrane of uterine epithelial cells during the early stages of pregnancy in the rat. Lesions caused by digitonin complexing with cholesterol were seen on both lateral and apical portions of the membrane but tight junctions and desmosomes were lesion-free. Compared with day 1 of pregnancy, lesions on the apical plasma membrane were much more extensive and some were of different morphology on day 6 - the day of blastocyst implantation. We consider mechanisms of lesion formation and interpret the results to indicate a higher content and perhaps a different organization of cholesterol in the apical plasma membrane on day 6 of pregnancy. We also suggest how this increase may occur.


2001 ◽  
Vol 9 (3) ◽  
pp. 197-208 ◽  
Author(s):  
CR Murphy

The first site of contact between maternal and fetal tissue at the beginning of blastocyst attachment and implantation is the plasma membrane of uterine epithelial cells. Indeed, as has been noted often, regardless of the mode of placentation which ultimately occurs, contact between this plasma membrane and that of the trophoblast is a common beginning to implantation in most species studied so far, which now range from viviparous lizards to human beings. The similarities in these early events of uterine receptivity and placentation go further than mere contact between opposing surfaces however. A considerable body of evidence indicates that the behaviour of the plasma membrane of uterine epithelial cells during early pregnancy has many common aspects across species including humans. This review pays special attention to events in the human uterus and the epithelial cells in particular, but examines them within the wider context of uterine receptivity for implantation across species.


2010 ◽  
Vol 22 (9) ◽  
pp. 110
Author(s):  
R. J. Madawala ◽  
C. R. Murphy

Rat uterine epithelial cells undergo many changes during early pregnancy in order to become receptive to blastocyst implantation. These changes include basolateral folding and the presence of vesicles of various sizes which are at their greatest number during the pre-implantation period. The present study investigated the possible role that caveolin 1 and 2 plays in this remodelling specifically days 1, 3, 6, 7, and 9 of pregnancy. Caveolin is a major protein in omega shaped invaginations of the plasma membrane called caveolae that are considered to be specialised plasma membrane subdomains. Caveolae are rich in cholesterol, glycosphingolipids, and GPI anchored proteins and are involved in endocytosis and membrane curvature. Immunofluorescence microscopy has shown caveolin 1 and 2 on day 1 of pregnancy are localised to the cytoplasm of luminal uterine epithelial cells, and by day 6 of pregnancy (the time of implantation), it concentrates basally. By day 9 of pregnancy, expression of both caveolin 1 and 2 in luminal uterine epithelia is cytoplasmic as seen on day 1 of pregnancy. A corresponding increase in protein expression of caveolin 1 on day 6 of pregnancy in luminal uterine epithelia was observed. Interestingly however, caveolin 2 protein expression decreases at the time of implantation as found by western blot analysis. Both caveolin 1 and 2 were localised to blood vessels within the endometrium and myometrium and also the muscle of the myometrium in all days of pregnancy studied. In addition, both caveolin 1 and 2 were absent from glandular epithelium, which is interesting considering that they do not undergo the plasma membrane transformation. The localisation and expression of caveolin 1 and 2 in rat luminal uterine epithelium at the time of implantation suggest possible roles in trafficking of cholesterol and/or various proteins for either degradation or relocation. Caveolins may contribute to the morphology of the basolateral membrane seen on day 6 of pregnancy. All of which may play an important role during successful blastocyst implantation.


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