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A.H. Dahlmann, M. Eastwood, M. Bailly, P.T. Khaw; Mechanisms of Force Generation and Tissue Contraction by Ocular Fibroblasts – Simultaneous Microscopy and Force Measurements . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2697.
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© ARVO (1962-2015); The Authors (2016-present)
To study mechanisms of matrix contraction by ocular fibroblasts (OF) and modulation by drugs.
We used human corneal, Tenon and scleral fibroblasts (CF, TF, SF) in a standard collagen matrix. Using a simultaneous imaging and micro–culture force monitor system (SIM–CFM), we measured the tension generated by cells and simultaneously imaged cell behaviour, matrix remodeling (Fig.1: OF interacting with matrix), and their modulation by myosin light chain kinase and MMP inhibitors (ML9, Ilomastat) with phase and confocal reflection timelapse microscopy. Openlab and Metamorph software packages were used for data analysis.
The OF studied show marked differences in contractile activity. Whilst CF contract matrix by 55% within the first 24h, the same number of TF only contract it by 10%. Whilst contraction by CF quickly reaches a plateau, TF generate sustained contraction. Final matrix contraction is the same. SF only contract matrix at higher cell density. CF generate the greatest force; TF generate 2/3 less, and SF hardly any. Three main factors determine contraction efficiency: cell volume (CF>TF>SF), cell protrusive and retractile activity (dynamic index, DI), and efficient binding to matrix fibrils. DI mirrors force generation. ML9 reduces DI and force generation. Ilomastat has a modest effect on DI and force, but dramatically inhibit matrix contraction, indicating that additional mechanisms are involved.
OF are involved in a variety of ocular conditions: glaucoma, corneal scarring, and subconjunctival scarring after glaucoma surgery. This work is the first to quantitatively assess the mechanisms of matrix contraction by different OF. In addition, it directly visualizes the contraction–modulating effect of two new classes of drugs, which might become important in the treatment of clinical conditions.
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