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Author Notes:

Correspondence: Johnna S. Temenoff, T: 1-404-385-5026; F: 1-404-894-4243; johnna.temenoff@bme.gatech.edu.

Authors' Contributions: ANP contributed to the research design, acquired, analyzed, and interpreted the zymography data, and wrote the paper.

JMF acquired, analyzed, and interpreted all micro-computed tomography (μCT) data and histological data, as well as contributed to drafting the paper.

AC assisted with acquiring and analyzing the histological scoring data. EPY assisted with acquiring and analyzing zymography data.

REG helped develop design, acquisition, and analysis of the μCT and contributed to critical revision of the paper.

MOP and JST developed all research designs, analysis, and interpretation of all data, and contributed to critical revisions of the paper.

All authors have read and approved the final submitted manuscript.

Acknowledgments: The authors would like to thank Torri Rinker, Liane Tellier, Jennifer Lei, Molly Ogle, and Jack Krieger for serving as graders for tendon image scoring.

The authors would also like to thank Erin Radcliffe for her assistance in processing samples.

Disclosures: This content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Subjects:

Research Funding:

Grant sponsor: National Institute of Arthritis and Musculoskeletal; Grant sponsor: Skin Diseases of the National Institutes of Health; Grant number: R01AR063692; Grant sponsor: National Institutes of Health Cell and Tissue Engineering Training; Grant number: T32GM008433.

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Orthopedics
  • overuse injury
  • supraspinatus tendon
  • cartilage
  • micro-computed tomography
  • zymography
  • ROTATOR CUFF TEAR
  • HUMAN OSTEOARTHRITIC CARTILAGE
  • CATHEPSIN-K
  • MATRIX METALLOPROTEINASES
  • ANIMAL-MODELS
  • CYSTEINE CATHEPSINS
  • GLENOID CARTILAGE
  • V ACTIVITY
  • EXPRESSION
  • TENDINOPATHY

Supraspinatus tendon overuse results in degenerative changes to tendon insertion region and adjacent humeral cartilage in a rat model

Tools:

Journal Title:

Journal of Orthopaedic Research

Volume:

Volume 35, Number 9

Publisher:

, Pages 1910-1918

Type of Work:

Article | Post-print: After Peer Review

Abstract:

The etiology of rotator cuff tendon overuse injuries is still not well understood. Furthermore, how this overuse injury impacts other components of the glenohumeral joint, including nearby articular cartilage, is also unclear. Therefore, this study sought to better understand the time course of tendon protease activity in a rat model of supraspinatus overuse, as well as determine effects of 10 weeks of overuse on humeral head articular cartilage. For these studies, multiplex gelatin zymography was used to characterize protease activity profiles in tendon and cartilage, while histological scoring/mechanical testing and micro-computed tomography (μCT) imaging were used to quantify structural damage in the supraspinatus tendon insertion and humeral articular cartilage, respectively. Histological scoring of supraspinatus tendon insertions revealed tendinopathic cellular and collagen fiber changes after 10 weeks of overuse when compared to controls, while mechanical testing revealed no significant differences between tensile moduli (overuse: 24.5 ± 11.5 MPa; control: 16.3 ± 8.7 MPa). EPIC-μCT imaging on humeral articular cartilage demonstrated significant cartilage thinning (overuse: 119.6 ± 6.34 μm; control: 195.4 ± 13.4μm), decreased proteoglycan content (overuse: 2.1 ± 0.18 cm−1; control: 1.65 ± 0.14 cm−1), and increased subchondral bone thickness (overuse: 216.2 ± 10.9 μm; control: 192 ± 17.8μm) in the overuse animals. Zymography results showed no significant upregulation of cathepsins or matrix metalloproteinases in tendon or cartilage at 2 or 10 weeks of overuse compared to controls. These results have further elucidated timing of protease activity over 10 weeks and suggest that damage occurs to other tissues in addition to the supraspinatus tendon in this overuse injury model.

Copyright information:

© 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

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