Biomedical subjects

Laura A Lindsay

Publications and source records attributed to Laura A Lindsay.

5 recordsLinked to original sources

PubMed2006

Desmosomes in uterine epithelial cells decrease at the time of implantation: an ultrastructural and morphometric study.

Displacement of uterine epithelial cells is an important aspect of implantation in the rat and other species, allowing invasion of the blastocyst into the endometrial stroma. Desmosomes, which are part of the lateral junctional complex, function in cell-to-cell adhesion, and are therefore likely to be involved in displacement of uterine epithelial cells at the time of implantation. This study used transmission electron microscopy to study rat uterine epithelial cells during the peri-implantation period to investigate the change in the number of structural desmosomes along the lateral plasma membrane of uterine epithelial cells. We found a significant decrease in the number of desmosomes along the entire lateral plasma membrane as pregnancy progressed. Furthermore, there were also significant decreases in the number of desmosomes on the apical portion of the lateral plasma membrane between all days of pregnancy examined. In addition, on day 6 of pregnancy, the time of attachment, desmosomes were larger and seen as "giant desmosomes." For the first time, this study has shown that there is a significant reduction in cell height and actual number of ultrastructurally observable desmosomes at the time of implantation in the rat. It is proposed that this reduction in desmosome number leads to a decrease in lateral adhesion between uterine epithelial cells at the time of implantation, and hence is involved in the loss of uterine epithelial cells to facilitate blastocyst invasion.

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PubMed2006

Redistribution of aquaporins 1 and 5 in the rat uterus is dependent on progesterone: a study with light and electron microscopy.

During early pregnancy in the rat there is a dramatic reduction in luminal fluid which is associated with uterine receptivity for blastocyst implantation. This study investigates the presence and distributional changes of several members of the aquaporin (AQP) family in the rat uterus in response to hormonal regime. An increase in apical AQP5 protein expression was found in response to progesterone alone or in combination with oestrogen, which is similar to that seen at the time of implantation. AQP1 was found in endothelial cells of the endometrium and in the inner circular layer of smooth muscle, with maximal protein expression seen after three doses of progesterone plus 8 hr of oestrogen treatment. These results, for the first time, show that the up-regulation of AQP5 in the apical plasma membrane of uterine epithelial cells and AQP1 in the inner circular layer of myometrium, is dependent on progesterone. Furthermore, unlike during normal pregnancy, there is no differential gradient of AQP5 expression between mesometrial and antimesometrial poles of the progesterone treated uterus. Hence it is suggested that the differential gradient of AQP5 is dependent on the presence of a blastocyst, in addition to the appropriate hormonal environment.

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PubMed2004

Redistribution of aquaporins in uterine epithelial cells at the time of implantation in the rat.

The aim of this study was to investigate the presence of aquaporins 1, 4 and 5 in uterine epithelial cells during the early stages of pregnancy in the rat. Immunofluorescent and immunogold techniques showed that there was a shift of aquaporin 5 to the apical surface of uterine epithelial cells in the mesometrial pole of the uterus at the time of implantation. This study also revealed the absence of aquaporin 4 in the rat uterus during early pregnancy. Aquaporin 1 was observed in stromal blood vessels but there was no change in uterine epithelial cells during early pregnancy. These results suggest that aquaporin 5 plays an important role in the removal of uterine luminal fluid at the time of implantation in the rat and may contribute to the antimesometrial positioning of the implanting blastocyst.

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PubMed2004

Progesterone treatment and the progress of early pregnancy reduce desmoglein 1&2 staining along the lateral plasma membrane in rat uterine epithelial cells.

Uterine epithelium undergoes dramatic changes during early pregnancy in preparation for implantation. We have studied distribution patterns of the desmosomal marker, desmoglein 1&2, in rat uterine epithelial cells during early pregnancy as well as in hormonally stimulated ovariectomised animals. On day 1 of pregnancy as well as in oestradiol treated rats, desmoglein 1&2 staining was localized along the entire length of the lateral plasma membrane. By day 3 and on subsequent days of pregnancy as well as in ovariectomised animals treated with progesterone alone or in combination with oestradiol, desmoglein 1&2 staining was concentrated at the apical portion of the lateral plasma membrane. We suggest that the reorganisation of these desmosomal cadherins is an important component of uterine epithelial receptivity and this relocation is under the control of the ovarian hormone progesterone.

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PubMed2004

Aquaporin-1 increases in the rat myometrium during early pregnancy.

Immunofluorescence and immunogold techniques were used to determine the presence and distribution of aquaporin-1 (AQP1) within the rat uterus. Uterine tissue from non-pregnant (proestrus) as well as pregnant (days 1, 3, 6 and 7) rats were used. It was found that this water channel was present in the myometrium of the pregnant rat uterus with the intensity of AQP1 immunoreactivity increasing from day 1 to day 6 of pregnancy. In particular, an increase was also observed in mesometrial as compared to antimesometrial myometrium. Immunolocalization at the electron microscope level indicated that AQP1 was localized to the plasma membrane of smooth muscle cells found within the inner circular layer. It is suggested that AQP1 plays a role in stromal oedema, uterine closure and orientation of the blastocyst.

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