Posters

Tendon-like cells in the sclera respond to inflammatory stimulation

Poster Details

First Author: G.Atta GERMANY

Co Author(s):    F. Schroedl   A. Traweger   H. Tempfer   L. Heindl           

Abstract Details

Purpose:

Sclera is a tissue rich of the collagenous extracellular matrix which is built up and maintained by relatively few, still poorly characterized fibroblast-like cells. In case of injury or scleritis, the matrix is compromised. This situation is similar in tendon tissue, therefore the aim of this study to analyze scleral cells regarding their expression of tendon cell-associated markers and the response of these cells to inflammatory stimulation

Setting:

This is an experimental laboratory study on a transgenic mouse model involving descriptive histology and ex- vivo analyses.

Methods:

Sclera tissue of Scleraxis-GFP (Scx-GFP) mice was analyzed by immunohistochemistry for their expression of the tendon cell-associated marker gene Scleraxis. In organotypic tissue culture, sclera explants of adult Scx-GFP mice were exposed to 10ng/ml recombinant IL1-ß or 10ng/ml IL-1ß combined with 10 nM Dexamethasone, respectively. The tissues were then analyzed by immunofluorescence for the expression of inflammation- and fibrosis-associated proteins, as well as for damaged collagen, using Collagen Hybridizing Peptide, a technique for the detection of degraded & damaged collagen fibers. Semi-quantitative analysis was performed by calculating the percentage area of positive fluorescent signals.

Results:

Immunofluorescence analysis revealed a Scleraxis positive cell population in the sclera of both E17 embryos and adults’ mice. In-vitro stimulation of Scx-GFP mouse scleral tissue with IL1-ß leads to marked collagen damage within 3 days, as visualized by collagen hybridizing peptide (CHP). This effect is abrogated by co-incubation with 10nM Dexamethasone. In vitro stimulation of Scx-GFP mouse scleral tissue with IL1-ß Leads to significantly increased expression of the inflammation associated proteins COX2 and IL6, and the fibrosis associated marker proteins Connective Tissue Growth Factor (CTGF), Matrix Metalloproteinases 2, 3, and 13. This effect is abrogated by addition of 10nM dexamethasone.

Conclusions:

With this work, we show for the first time that scleral fibroblast cells express the tendon associated marker Scleraxis. Organotypic, in vitro exposure of sclera tissue to IL1-ß, induces inflammation- and fibrosis associated events in these cells. This is a novel in vitro model of scleritis, allowing to study early mechanisms in scleral inflammation.

Financial Disclosure:

None