The effects of cytokines in a cartilage explant model system

2.50
Hdl Handle:
http://hdl.handle.net/10547/622160
Title:
The effects of cytokines in a cartilage explant model system
Authors:
Stephan, Simon
Abstract:
Arthritis is a pathological condition whereby a persistent inflammatory response leads to breakdown of articular cartilage in synovial joints. Cartilage is a specialised avascular tissue containing chondrocytes embedded in an extracellular matrix. The cartilage matrix is composed of collagen to provide strength with aggregated proteoglycan to facilitate hydration. Cartilage has been reported to loose proteoglycans with concordant loss of integrity observed in arthritic disease pathology. Proteoglycans loss from cartilage has also been reported in in vitro models. Application of interleukin-1 (lL-1β) to cartilage in vitro has been demonstrated to increase loss of proteoglycans and modulate production of inflammatory mediators such as Nitric Oxide (NO) and Prostaglandin-E2 (PGE2). NO and PGE2 have also been associated with cartilage breakdown. Other cytokines such as colony stimulating factors (CSFs) may regulate cartilage function. The aim of this study was to select a cartilage explant system and compare the effects of interleukin-1 (lL-1) with those of colony stimulating factors (CSFs) by measuring the production of NO and PGE2 and release of proteoglycans. It was found that IL-1β increased PGE2 and NO production, but not loss of proteoglycans from rat cartilage explants. Granulocyte-CSF (G-CSF) and lL-3 increased production of NO and PGE2, respectively. When combined, IL-1β / Granulocyte-Macrophage (GM-CSF) increased production of PGE2 and G-CSF / IL-1β produced increased proteoglycan loss from explants. The model was then modified by integrating Swiss 3T3 Fibroblasts monolayers with explants. Fibroblasts were initially screened to determine their separate response to these cytokines. Fibroblasts did not release proteoglycans into the culture media, but produced elevated concentrations of NO and PGE2 in response to IL-lβ.·Fibroblast-cartilage co-cultures treated with IL-lβ produced increased NO, PGE2 and proteoglycan release. G-CSF, GM-CSF and IL-3 caused increased levels of PGE2 in co-cultures, however, IL-1β was required to generate significant proteoglycan loss from cartilage explants. Finally, extra-cellular signal related protein kinases I and 2 (ERK 1&2) and p38 intracellular signalling pathways were shown to be involved in IL-1β mediated production of NO fibroblasts and explants. These studies show that IL-1β has increased potential to mediate cartilage breakdown when interacting with other cytokines, such as G-CSF, and other cell types, such as Swiss 3T3 fibroblasts. IL-1β has defined intracellular signalling pathways that may produce a range of responses in cartilage explants and fibroblasts. These studies may relate to production of inflammatory processes and loss of cartilage integrity and function in pathological conditions.
Citation:
Stephan, S. (2001) 'The effects of cytokines in a cartilage explant model system'. PhD thesis. University of Luton.
Publisher:
University of Bedfordshire
Issue Date:
Jan-2001
URI:
http://hdl.handle.net/10547/622160
Type:
Thesis or dissertation
Language:
en
Description:
A thesis submitted to the Faculty of Science, Technology and Design, University of Luton, in partial fulfilment of the requirements for the degree of Doctor of Philosophy.
Appears in Collections:
PhD e-theses

Full metadata record

DC FieldValue Language
dc.contributor.authorStephan, Simonen
dc.date.accessioned2017-08-03T11:53:47Z-
dc.date.available2017-08-03T11:53:47Z-
dc.date.issued2001-01-
dc.identifier.citationStephan, S. (2001) 'The effects of cytokines in a cartilage explant model system'. PhD thesis. University of Luton.en
dc.identifier.urihttp://hdl.handle.net/10547/622160-
dc.descriptionA thesis submitted to the Faculty of Science, Technology and Design, University of Luton, in partial fulfilment of the requirements for the degree of Doctor of Philosophy.en
dc.description.abstractArthritis is a pathological condition whereby a persistent inflammatory response leads to breakdown of articular cartilage in synovial joints. Cartilage is a specialised avascular tissue containing chondrocytes embedded in an extracellular matrix. The cartilage matrix is composed of collagen to provide strength with aggregated proteoglycan to facilitate hydration. Cartilage has been reported to loose proteoglycans with concordant loss of integrity observed in arthritic disease pathology. Proteoglycans loss from cartilage has also been reported in in vitro models. Application of interleukin-1 (lL-1β) to cartilage in vitro has been demonstrated to increase loss of proteoglycans and modulate production of inflammatory mediators such as Nitric Oxide (NO) and Prostaglandin-E2 (PGE2). NO and PGE2 have also been associated with cartilage breakdown. Other cytokines such as colony stimulating factors (CSFs) may regulate cartilage function. The aim of this study was to select a cartilage explant system and compare the effects of interleukin-1 (lL-1) with those of colony stimulating factors (CSFs) by measuring the production of NO and PGE2 and release of proteoglycans. It was found that IL-1β increased PGE2 and NO production, but not loss of proteoglycans from rat cartilage explants. Granulocyte-CSF (G-CSF) and lL-3 increased production of NO and PGE2, respectively. When combined, IL-1β / Granulocyte-Macrophage (GM-CSF) increased production of PGE2 and G-CSF / IL-1β produced increased proteoglycan loss from explants. The model was then modified by integrating Swiss 3T3 Fibroblasts monolayers with explants. Fibroblasts were initially screened to determine their separate response to these cytokines. Fibroblasts did not release proteoglycans into the culture media, but produced elevated concentrations of NO and PGE2 in response to IL-lβ.·Fibroblast-cartilage co-cultures treated with IL-lβ produced increased NO, PGE2 and proteoglycan release. G-CSF, GM-CSF and IL-3 caused increased levels of PGE2 in co-cultures, however, IL-1β was required to generate significant proteoglycan loss from cartilage explants. Finally, extra-cellular signal related protein kinases I and 2 (ERK 1&2) and p38 intracellular signalling pathways were shown to be involved in IL-1β mediated production of NO fibroblasts and explants. These studies show that IL-1β has increased potential to mediate cartilage breakdown when interacting with other cytokines, such as G-CSF, and other cell types, such as Swiss 3T3 fibroblasts. IL-1β has defined intracellular signalling pathways that may produce a range of responses in cartilage explants and fibroblasts. These studies may relate to production of inflammatory processes and loss of cartilage integrity and function in pathological conditions.en
dc.language.isoenen
dc.publisherUniversity of Bedfordshireen
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/*
dc.subjectB120 Physiologyen
dc.subjectexplantsen
dc.subjectcartilageen
dc.subjectproteoglycanen
dc.subjectcytokinesen
dc.titleThe effects of cytokines in a cartilage explant model systemen
dc.typeThesis or dissertationen
dc.type.qualificationnamePhDen_GB
dc.type.qualificationlevelPhDen
dc.publisher.institutionUniversity of Bedfordshireen
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