Second harmonic generation analysis of early Achilles tendinosis in response to <it>in vivo </it>mechanical loading

<p>Abstract</p> <p>Background</p> <p>Tenocytes have been implicated in the development of tendinosis, a chronic condition commonly seen in musculoskeletal overuse syndromes. However, the relation between abnormal tenocyte morphology and early changes in the fibrillar co...

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Main Authors: Fong Gloria, Abraham Thomas, Scott Alex
Format: Article
Language:English
Published: BMC 2011-01-01
Series:BMC Musculoskeletal Disorders
Online Access:http://www.biomedcentral.com/1471-2474/12/26
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author Fong Gloria
Abraham Thomas
Scott Alex
author_facet Fong Gloria
Abraham Thomas
Scott Alex
author_sort Fong Gloria
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Tenocytes have been implicated in the development of tendinosis, a chronic condition commonly seen in musculoskeletal overuse syndromes. However, the relation between abnormal tenocyte morphology and early changes in the fibrillar collagen matrix has not been closely examined <it>in vivo</it>. Second harmonic generation (SHG) microscopy is a recently developed technique which allows examination of fibrillar collagen structures with a high degree of specificity and resolution. The goal of this study was to examine the potential utility of SHG and multiphoton excitation fluorescence (MPEF) microscopy in understanding the relation between tenocytes and their surrounding collagenous matrix in early tendon overuse lesions.</p> <p>Methods</p> <p>Histological preparations of tendon were prepared from adult male Sprague-Dawley rats subjected to an Achilles tendon loading protocol for 12 weeks (Rat-A-PED), or from sedentary age-matched cage controls. Second harmonic generation and multiphoton excitation fluorescence were performed simultaneously on these tissue sections in at least three different areas.</p> <p>Results</p> <p>SHG microscopy revealed an association between abnormal tenocyte morphology and morphological changes in the fibrillar collagen matrix of mechanically loaded Achilles tendons. Collagen density and organization was significantly reduced in focal micro-regions of mechanically loaded tendons. These pathological changes occurred specifically in association with altered tenocyte morphology. Normal tendons displayed a regular distribution of fibre bundles, and the average size of these bundles as determined by Gaussian analysis was 0.47 μm ± 0.02. In comparison, fibre bundle measures from tendon regions in the vicinity of abnormal tenocytes could not be quantified due to a reduction in their regularity of distribution and orientation.</p> <p>Conclusions</p> <p>SHG microscopy allowed high resolution detection of focal tendon abnormalities affecting the fibrillar collagen matrix. With ongoing repetitive loading, these tenocyte-associated focal collagen defects could predispose to the progression of overuse pathology.</p>
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spelling doaj.art-b91d02e977ea42d0a93bf8937c8a05f62022-12-21T19:13:45ZengBMCBMC Musculoskeletal Disorders1471-24742011-01-011212610.1186/1471-2474-12-26Second harmonic generation analysis of early Achilles tendinosis in response to <it>in vivo </it>mechanical loadingFong GloriaAbraham ThomasScott Alex<p>Abstract</p> <p>Background</p> <p>Tenocytes have been implicated in the development of tendinosis, a chronic condition commonly seen in musculoskeletal overuse syndromes. However, the relation between abnormal tenocyte morphology and early changes in the fibrillar collagen matrix has not been closely examined <it>in vivo</it>. Second harmonic generation (SHG) microscopy is a recently developed technique which allows examination of fibrillar collagen structures with a high degree of specificity and resolution. The goal of this study was to examine the potential utility of SHG and multiphoton excitation fluorescence (MPEF) microscopy in understanding the relation between tenocytes and their surrounding collagenous matrix in early tendon overuse lesions.</p> <p>Methods</p> <p>Histological preparations of tendon were prepared from adult male Sprague-Dawley rats subjected to an Achilles tendon loading protocol for 12 weeks (Rat-A-PED), or from sedentary age-matched cage controls. Second harmonic generation and multiphoton excitation fluorescence were performed simultaneously on these tissue sections in at least three different areas.</p> <p>Results</p> <p>SHG microscopy revealed an association between abnormal tenocyte morphology and morphological changes in the fibrillar collagen matrix of mechanically loaded Achilles tendons. Collagen density and organization was significantly reduced in focal micro-regions of mechanically loaded tendons. These pathological changes occurred specifically in association with altered tenocyte morphology. Normal tendons displayed a regular distribution of fibre bundles, and the average size of these bundles as determined by Gaussian analysis was 0.47 μm ± 0.02. In comparison, fibre bundle measures from tendon regions in the vicinity of abnormal tenocytes could not be quantified due to a reduction in their regularity of distribution and orientation.</p> <p>Conclusions</p> <p>SHG microscopy allowed high resolution detection of focal tendon abnormalities affecting the fibrillar collagen matrix. With ongoing repetitive loading, these tenocyte-associated focal collagen defects could predispose to the progression of overuse pathology.</p>http://www.biomedcentral.com/1471-2474/12/26
spellingShingle Fong Gloria
Abraham Thomas
Scott Alex
Second harmonic generation analysis of early Achilles tendinosis in response to <it>in vivo </it>mechanical loading
BMC Musculoskeletal Disorders
title Second harmonic generation analysis of early Achilles tendinosis in response to <it>in vivo </it>mechanical loading
title_full Second harmonic generation analysis of early Achilles tendinosis in response to <it>in vivo </it>mechanical loading
title_fullStr Second harmonic generation analysis of early Achilles tendinosis in response to <it>in vivo </it>mechanical loading
title_full_unstemmed Second harmonic generation analysis of early Achilles tendinosis in response to <it>in vivo </it>mechanical loading
title_short Second harmonic generation analysis of early Achilles tendinosis in response to <it>in vivo </it>mechanical loading
title_sort second harmonic generation analysis of early achilles tendinosis in response to it in vivo it mechanical loading
url http://www.biomedcentral.com/1471-2474/12/26
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AT scottalex secondharmonicgenerationanalysisofearlyachillestendinosisinresponsetoitinvivoitmechanicalloading