Investigation of the effects of Mechanical Strain in Human Tenocytes

Jones, Eleanor (2012) Investigation of the effects of Mechanical Strain in Human Tenocytes. Doctoral thesis, University of East Anglia.

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    Abstract

    Tendinopathies are a range of diseases characterised by pain and insidious degeneration. Although poorly understood, onset is often associated with physical activity. Metalloproteinases are regulated differentially in tendinopathy causing disruptions in extracellular matrix (ECM) homeostasis. An increase in the anti-inflammatory cytokine TGFβ has also been documented. This project aims to investigate the effect of cyclic tensile strain loading and TGFβ stimulation on protease and ECM protein expression by human tenocytes and begin to characterise the pathway of mechanotransduction.
    Human tenocytes were seeded at 1.5x106 cells/ml into collagen gels (rat tail type I, 1mg/ml) and stretched using a sinusoidal waveform of 0-5% at 1Hz using the Flexcell FX4000T™ system. Cultures were treated with or without 1ng/ml TGFβ1 or inhibitors of TGFβRI, metalloproteinases, RGD, Mannose-6-phosphate, integrin β1 and a thrombospondin as appropriate. qRT-PCR and a cell based luciferase assay were used to assess RNA and TGFβ activity respectively.
    The prolonged application of 5% cyclic mechanical strain in a 3D culture system induced an anabolic response in protease and matrix genes. In most genes changes in gene expression with loading was mirrored with TGFβ stimulation. We also demonstrated that the inhibition of the TGFβRI abrogated the strain induced changes in mRNA. TGFβ activity was increased with 48 hours mechanical strain although there was no increase in mRNA or total TGFβ. This indicates that TGFβ activation plays an important role in the mechanoregulation of gene expression. Inhibition of potential mechanisms of TGFβ activation including; serine protease or metalloproteinase activity, integrin or thrombospondin interaction with latent TGFβ showed no effect upon TGFβ activation or gene regulation with strain. Therefore strain mediated TGFβ activation may occur via a novel mechanism. By understanding mechanotransduction, we may be able to determine whether dysregulation of this system is involved in the development of tendinopathy.

    Item Type: Thesis (Doctoral)
    Faculty \ School: Faculty of Science > School of Biological Sciences
    Depositing User: Mia Reeves
    Date Deposited: 02 May 2013 10:09
    Last Modified: 02 May 2013 10:09
    URI: https://ueaeprints.uea.ac.uk/id/eprint/42329
    DOI:

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