Tendon extracellular matrix damage, degradation and inflammation in response to in-vitro overload exercise

Ewa M Spiesz, Chavaunne T Thorpe, Saira Chaudhry, Graham P Riley, Helen L Birch, Peter D Clegg, Hazel R C Screen

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56 Citations (Scopus)

Abstract

The role of inflammation in tendon injury is uncertain and a topic of current interest. In vitro studies of tendon accelerated overload damage can serve as a valuable source of information on the early stages of tendinopathy. Viable fascicle bundles from bovine flexor tendons were subjected to cyclic uniaxial loading from 1-10% strain. Immunostaining for inflammatory markers and matrix degradation markers was performed on the samples after mechanical testing. Loaded samples exhibited visible extracellular matrix damage, with disrupted collagen fibres and fibre kinks, and notable damage to the interfascicular matrix. Inflammatory markers COX-2 and IL-6 were only expressed in the cyclically loaded samples. Collagen degradation markers MMP-1 and C1,2C were colocalised in many areas, with staining occurring in the interfascicular matrix or the fascicular tenocytes. These markers were present in control samples, but staining became increasingly intense with loading. Little MMP-3 or MMP-13 was evident in control sections. In loaded samples, some sections showed intense staining of these markers, again localised to interfascicular regions. This study suggests that inflammatory markers may be expressed rapidly after tendon overload exercise. Interestingly, both inflammation and damage-induced matrix remodelling seem to be concentrated in, or in the vicinity of, the highly cellular interfascicular matrix. This article is protected by copyright. All rights reserved.
Original languageEnglish
Pages (from-to)889–897
JournalJournal of Orthopaedic Research
Volume33
Issue number6
DOIs
Publication statusPublished - 26 Feb 2015

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