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Rabbit tendon cells produce MMP-3 in response to fluid flow without significant calcium transients

Faculty of Kinesiology, Human Performance Laboratory, University of Calgary, 2500 University Drive, NW Calgary, Alberta, Canada T2N 1N4.
Journal of Biomechanics (Impact Factor: 2.5). 04/2002; 35(3):303-9. DOI: 10.1016/S0021-9290(01)00217-2
Source: PubMed

ABSTRACT Forces applied to tendon during movement cause cellular deformation, as well as fluid movement. The goal of this study was to test the hypothesis that rabbit tendon fibroblasts detect and respond to fluid-induced shear stress. Cells were isolated from the paratenon of the rabbit Achilles tendon and then subjected to fluid flow at 1 dyn/cm(2) for 6h in a specially designed multi-slide flow device. The application of fluid flow led to an increased expression of the collagenase-1 (MMP-1), stromelysin-1 (MMP-3), cyclooxygenase II (COX-2) and interleukin-1beta (IL-1beta) genes. The release of proMMP-3 into the medium exhibited a dose-response with the level of fluid shear stress. However, not all cells aligned in the direction of flow. In other experiments, the same cells were incubated with the calcium-reactive dye FURA-2 AM, then subjected to laminar fluid flow in a parallel plate flow chamber. The cells did not significantly increase intracellular calcium concentration when exposed to fluid shear stress levels of up to 25 dyn/cm(2). These results show that gene expression in rabbit tendon cells is sensitive to fluid flow, but that signal transduction is not dependent on intracellular calcium transients. The upregulation of the MMP-1, MMP-3 and COX-2 genes shows that fluid flow could be an important mechanical stimulus for tendon remodelling or injury.

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Available from: Albert J Banes, Aug 17, 2015
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    • "This population proliferates and increases overall synthesis of extracellular matrix proteins in tendon in response to exercise (Zhang et al. 2010). Tendon cells' in vitro responses to mechanical stimuli have been studied using silicone substrates applying simultaneous substrate deformation and fluid flow (Thompson et al. 2011), with low strain magnitude effects promoting anabolic activity, that is secretion of extracellular matrix proteins, and higher magnitudes more catabolic, that is, secretion of enzymes responsible for breaking down extracellular matrix proteins (Yang and Im 2005; Archambault et al. 2002; Yang et al. 2004). "
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    • "However, even at high fluid-shear rates and with the induction of collagenase, there is no significant calcium influx in tendon cells (Archambault et al. 2002). Thus, gene expression may be activated through different mechanotransduction mechanisms (kinases, stretch-activated ion channels) depending on the mechanical signal experienced by the cell (Archambault et al. 2002). Indeed, kinases are cell membrane proteins that are phosphorylated when subjected to cyclic stretching or shear stress (Arnoczky et al. 2002b; Iwasaki et al. 2000; Wang 2006). "
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    • "But the tensional forces increased both the MMP-2 and Col-I. Archambault [2] showed that rabbit tendon fibroblasts responded to fluid-induced shear stress by increasing the release of pro-MMP-3 in a dose–response manner with the level of fluid shear stress. AdamÕs result indicated that prolonged spinal loading induced MMP-2 activation in intervertebral disc [22]. "
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