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Tensile strain increased COX-2 expression and PGE2 release leading to weakening of the human amniotic membrane

Tensile strain increased COX-2 expression and PGE2 release leading to weakening of the human amniotic membrane
Tensile strain increased COX-2 expression and PGE2 release leading to weakening of the human amniotic membrane
INTRODUCTION:

There is evidence that premature rupture of the fetal membrane at term/preterm is a result of stretch and tissue weakening due to enhanced prostaglandin E2 (PGE2) production. However, the effect of tensile strain on inflammatory mediators and the stretch sensitive protein connexin-43 (Cx43) has not been examined. We determined whether the inflammatory environment influenced tissue composition and response of the tissue to tensile strain.

METHODS:

Human amniotic membranes isolated from the cervix (CAM) or placenta regions (PAM) were examined by second harmonic generation to identify collagen orientation and subjected to tensile testing to failure. In separate experiments, specimens were subjected to cyclic tensile strain (2%, 1 Hz) for 24 h. Specimens were examined for Cx43 by immunofluorescence confocal microscopy and expression of COX-2 and Cx43 by RT-qPCR. PGE2, collagen, elastin and glycosaminoglycan (GAG) levels were analysed by biochemical assay.

RESULTS:

Values for tensile strength were significantly higher in PAM than CAM with mechanical parameters dependent on collagen orientation. Gene expression for Cx43 and COX-2 was enhanced by tensile strain leading to increased PGE2 release and GAG levels in PAM and CAM when compared to unstrained controls. In contrast, collagen and elastin content was reduced by tensile strain in PAM and CAM.

DISCUSSION:

Fibre orientation has a significant effect on amniotic strength. Tensile strain increased Cx43/COX-2 expression and PGE2 release resulting in tissue softening mediated by enhanced GAG levels and a reduction in collagen/elastin content.

CONCLUSION:

A combination of inflammatory and mechanical factors may disrupt amniotic membrane biomechanics and matrix composition.
macrolide, placenta, perfusion, intrauterine infection, inflammation
0143-4004
1057-1064
Chowdhury, B.
f3b7d6bb-241e-4bf7-b6b5-0a2d04097814
David, A.L.
505e1ec6-34d2-489d-b2af-7294f8516fe3
Thrasivoulou, C.
1ba0bd60-540a-4525-9b85-352e341a6228
Becker, D.L.
0afad465-ce91-4512-bce3-6ccf37c2f04c
Bader, D.L.
9884d4f6-2607-4d48-bf0c-62bdcc0d1dbf
Chowdhury, T.T.
3969bc1d-acec-4cad-b523-c8b4885fcb0a
Chowdhury, B.
f3b7d6bb-241e-4bf7-b6b5-0a2d04097814
David, A.L.
505e1ec6-34d2-489d-b2af-7294f8516fe3
Thrasivoulou, C.
1ba0bd60-540a-4525-9b85-352e341a6228
Becker, D.L.
0afad465-ce91-4512-bce3-6ccf37c2f04c
Bader, D.L.
9884d4f6-2607-4d48-bf0c-62bdcc0d1dbf
Chowdhury, T.T.
3969bc1d-acec-4cad-b523-c8b4885fcb0a

Chowdhury, B., David, A.L., Thrasivoulou, C., Becker, D.L., Bader, D.L. and Chowdhury, T.T. (2014) Tensile strain increased COX-2 expression and PGE2 release leading to weakening of the human amniotic membrane. Placenta, 35 (12), Winter Issue, 1057-1064. (doi:10.1016/j.placenta.2014.09.006). (PMID:25280972)

Record type: Article

Abstract

INTRODUCTION:

There is evidence that premature rupture of the fetal membrane at term/preterm is a result of stretch and tissue weakening due to enhanced prostaglandin E2 (PGE2) production. However, the effect of tensile strain on inflammatory mediators and the stretch sensitive protein connexin-43 (Cx43) has not been examined. We determined whether the inflammatory environment influenced tissue composition and response of the tissue to tensile strain.

METHODS:

Human amniotic membranes isolated from the cervix (CAM) or placenta regions (PAM) were examined by second harmonic generation to identify collagen orientation and subjected to tensile testing to failure. In separate experiments, specimens were subjected to cyclic tensile strain (2%, 1 Hz) for 24 h. Specimens were examined for Cx43 by immunofluorescence confocal microscopy and expression of COX-2 and Cx43 by RT-qPCR. PGE2, collagen, elastin and glycosaminoglycan (GAG) levels were analysed by biochemical assay.

RESULTS:

Values for tensile strength were significantly higher in PAM than CAM with mechanical parameters dependent on collagen orientation. Gene expression for Cx43 and COX-2 was enhanced by tensile strain leading to increased PGE2 release and GAG levels in PAM and CAM when compared to unstrained controls. In contrast, collagen and elastin content was reduced by tensile strain in PAM and CAM.

DISCUSSION:

Fibre orientation has a significant effect on amniotic strength. Tensile strain increased Cx43/COX-2 expression and PGE2 release resulting in tissue softening mediated by enhanced GAG levels and a reduction in collagen/elastin content.

CONCLUSION:

A combination of inflammatory and mechanical factors may disrupt amniotic membrane biomechanics and matrix composition.

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More information

Accepted/In Press date: 11 September 2014
e-pub ahead of print date: 19 September 2014
Published date: December 2014
Keywords: macrolide, placenta, perfusion, intrauterine infection, inflammation
Organisations: Faculty of Health Sciences

Identifiers

Local EPrints ID: 373455
URI: http://eprints.soton.ac.uk/id/eprint/373455
ISSN: 0143-4004
PURE UUID: 130fd2d4-b44e-4d06-bfda-d1208ad82c68
ORCID for D.L. Bader: ORCID iD orcid.org/0000-0002-1208-3507

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Date deposited: 19 Feb 2015 11:19
Last modified: 14 Mar 2024 18:53

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Contributors

Author: B. Chowdhury
Author: A.L. David
Author: C. Thrasivoulou
Author: D.L. Becker
Author: D.L. Bader ORCID iD
Author: T.T. Chowdhury

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