Changes in the physical properties and in the collagen and hexosamine contents of the foetal membranes during pregnancy in the rat

Harkness, Margaret L. R.; Harkness, R. D.

doi:10.1113/jphysiol.1956.sp005541

Cited by 26 publications

(16 citation statements)

References 9 publications

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“…Lastly, on Day 21 the specific orientation of collagen bundles seen on Days 18-20 was absent. These structural alterations, which have not been previously described for rat fetal membranes, are consistent with the findings of Harkness and Harkness [12], who reported that weakening of rat fetal membranes was accompanied by a decline in collagen concentration.…”

Section: Discussionsupporting

confidence: 92%

“…A single early biochemical and physical study by Harkness and Harkness [12] showed that a decrease in collagen content of rat fetal membranes was accompanied by a decline in their physical strength. The approach these researchers used, however, did not permit a determination of the membrane(s) affected, i.e., VYSP, amnion, or both.…”

Section: Discussionmentioning

confidence: 98%

“…A single study in which the biochemical and physical properties of rat fetal membranes were examined indicated that a loss of collagen in the peripartal period was paralleled by a decline in membrane strength [12]. This implies that fetal membranes are undergoing important alterations in their architecture, presumably in anticipation of parturition.…”

Section: Introductionmentioning

confidence: 98%

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Striking Changes in the Structure and Organization of Rat Fetal Membranes Precede Parturition1

Paavola

Furth

Delgado

et al. 1995

Biology of Reproduction

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Premature rupture of fetal membranes can harm infant and mother. It is unclear whether structural changes predispose these membranes to breaking. We thus assessed rat visceral yolk sac placenta (VYSP) and amnion by light and by transmission electron microscopy on Days 18-21 of gestation. Light microscope sections were stained for connective tissue (extracellular matrix) components: collagen, glycoprotein, and glycosaminoglycans/proteoglycans. Some tissue was incubated with chondroitinase ABC. We observed that fetal membranes became increasingly fragile, rupturing readily on Day 21. On Days 18-20, the two epithelial layers of the capsular VYSP were separated by a well-developed, well-vascularized connective tissue layer that stained intensely for all matrix components studied; on Day 21, the connective tissue layer was thinner, moderately stained, and less vascularized. On Days 18-20, the two cellular layers of the amnion were separated by a narrow, compact connective tissue layer that stained modestly for all matrix components; on Day 21, this area was widened and stained faintly. Transmission electron microscopy showed that collagen fibrils of the amnion were abundant, closely packed, and well organized on Days 18-20, whereas on Day 21 they were few in number, widely spaced, and disorganized. Similar changes were present after incubation with chondroitinase ABC. In addition, amniotic epithelial cells were moribund and delaminating, basal laminae were deteriorating or absent, and few cells were at the outer surface of the amnion. All changes preceded parturition. We conclude that the structural integrity of rat fetal membranes is impaired before birth through the loss of connective tissue components and cells, changes that presumably underlie membrane rupture. Lastly, the similarity of structural changes in rat and human fetal membranes point to the potential usefulness of the rat model.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Striking Changes in the Structure and Organization of Rat Fetal Membranes Precede Parturition1

Paavola

Furth

Delgado

et al. 1995

Biology of Reproduction

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“…As pregnancy approaches term, the structure of the amnion VYSP changes as a prelude to parturition [1,2]. The amnion becomes a viscous gel, while the VYSP thins, particularly in the capsular region, and ultimately ruptures [2].…”

Section: Introductionmentioning

confidence: 99%

92-kDa Gelatinase (Matrix Metalloproteinase-9) is Induced in Rat Amnion Immediately Prior to Parturition1

Lei

Vadillo-Ortega

Paavola

et al. 1995

Biology of Reproduction

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The fetal membranes undergo striking changes in structure before delivery that involve catabolism of the extracellular matrix. To investigate the role of specific enzymes in this process, we examined gelatinase activities in rat amnion, visceral yolk sac placenta, and placenta and amniotic fluid between Days 18-21 of pregnancy. Matrix metalloproteinase (MMP)-2 was present in amnion on all days, and its activity increased slightly on Day 21. The 92-kDa gelatinase, MMP-9, was not detected on Days 18-20 but appeared by the morning of Day 21. There was a marked increase in MMP-9 mRNA in the amnion on Day 20, preceding the appearance of MMP-9 activity. Western blotting confirmed an increase in MMP-9 protein in amnion on Day 21. MMP-2 and MMP-9 activities were detected in extracts of whole yolk sac placenta, placenta, and amniotic fluid, but there were no striking changes in these gelatinases between Days 18 and 21. However, the capsular regions of the visceral yolk sac placentae, which thin and rupture during labor, did show higher MMP-9 activity on Day 21 than on Days 18 and 20. We suggest that the striking increase in MMP-9 expression in amnion and possibly the capsular region of the visceral yolk sac placenta approximately 12 h prior to delivery is responsible, in part, for the alterations in the structure of these fetal membranes before parturition.

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“…1A). deteriorate so that by late gestation it may be considered nonfunctional (9). Concomitant with the VYS decline, the fetal liver begins to increase the synthesis of proteins previously produced by the VYS (23).…”

Section: Resultsmentioning

confidence: 99%

Expression of a secreted transplantation antigen gene during murine embryogenesis.

Stein¹,

Barra²,

Jay³

et al. 1986

Mol. Cell. Biol.

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We examined the midgestation mouse embryo for transcripts related to the secreted transplantation antigen Q10 and show here that this gene is transcribed in the endoderm of the visceral yolk sac. Its level of expression is highest at day 14 and then declines as development proceeds. Concurrently with the decrease in yolk sac expression, the amount of transcripts accumulating in the fetal liver increases during late embryogenesis.The murine major histocompatibility complex encodes different classes of proteins that regulate the immune response. The analysis of class I-related cDNA clones derived from adult mouse liver RNA has recently led to the description of a novel class I antigen (5). The cDNA sequence of one clone predicted a protein which would have several polar amino acid substitutions followed by nonsense codons in the normally hydrophobic transmembrane domain and would therefore lack the carboxy-terminal cytoplasmic domain (12). Because of these considerations it was reasoned that if such a protein was synthesized, it would be secreted rather than membrane bound. Using antibodies raised against a peptide that would be derived from the modified transmembrane domain, a class I-related protein of the molecular weight predicted from the sequence was immunoprecipitated from adult mouse serum (15), and its synthesis was shown to be restricted to the liver (6, 15). Other studies mapped the gene to the Q10 locus of the Qa region in the major histocompatibility complex (18,19).Since the liver is not well developed until about day 12 in mouse embryonic development and does not mature until later in gestation (21), we were interested in whether another tissue might synthesize the Q10 antigen during embryogenesis. The visceral yolk sac (VYS) seemed a likely candidate since it is one of the first tissues to differentiate (8) and is known to synthesize a number of liver proteins (1,7,10,17). These properties cease in the latter stages of gestation and are then taken over by the developing liver. We report here that RNAs which show homology to a probe specific for the secreted class I antigen, Q10, are present in the VYS of the midgestation mouse embryo. MATERIALS AND METHODSDissection of mouse conceptuses. Mature female CD-1 mice (Charles River Breeding Laboratories, Inc., Wilmington, Mass.) were injected intraperitoneally with 1 IU of pregnant mare serum gonadotropin (Diosynth, Inc., Chicago, Ill.). Two days later, they were injected with 5 IU of human chorionic gonadotropin (Organon, West Orange, N.J.) and mated. The morning that a vaginal plug was found was considered day 1 of pregnancy. This amount of pregnant mare serum gonadotropin synchronized the estrous cycle without inducing superovulation and thereby increased the number of successful matings. * Corresponding author.At the appropriate day, conceptuses were dissected free of the uterus in phosphate-buffered saline. Each conceptus was then separated into placenta, parietal yolk sac (PYS) (trophectoderm and parietal endoderm), and VYS (visceral endoderm [VE] ...

show abstract

Changes in the physical properties and in the collagen and hexosamine contents of the foetal membranes during pregnancy in the rat

Cited by 26 publications

References 9 publications

Striking Changes in the Structure and Organization of Rat Fetal Membranes Precede Parturition1

Striking Changes in the Structure and Organization of Rat Fetal Membranes Precede Parturition1

92-kDa Gelatinase (Matrix Metalloproteinase-9) is Induced in Rat Amnion Immediately Prior to Parturition1

Expression of a secreted transplantation antigen gene during murine embryogenesis.

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