Related Experiment Video
Updated: Jun 16, 2026

Mechanical Stimulation of Chondrocyte-agarose Hydrogels
Published on: October 27, 2012
Matrix accumulation by articular chondrocytes during mechanical stimulation is influenced by integrin-mediated cell
Caroline Spiteri1, Igal Raizman, Robert M Pilliar
1CIHR-BioEngineering of Skeletal Tissue Team, Mount Sinai Hospital, University of Toronto, Toronto, Canada M5G 1X5.
Abstract:
We have shown previously that cyclic compression of newly forming bioengineered cartilage in vitro results in improved tissue formation via changes in expression of matrix metalloproteases, such as, MT1-MMP (membrane type metalloprotease), and increased synthesis of matrix molecules. Several studies have suggested an association between MT1-MMP and integrins, which are known to influence cell shape. Thus, the objectives of this study were to determine the effect of compressive mechanical stimulation on cell shape and the role of integrins and MT1-MMP in mediating these changes and influencing matrix accumulation. Bovine articular chondrocytes were grown on the surface of a porous ceramic substrate for 72 h and then cyclically compressed for 30 min. Scanning electron microscopy and morphometric analysis demonstrated that compression induced a rapid, transient increase in chondrocyte spreading by 10 min, followed by a retraction to prestimulated size within 6 h. This was associated with increased accumulation of newly synthesized proteoglycans, as determined by quantification of radioisotope incorporation. Blocking the alpha5beta1 integrin, or its beta1 subunit, inhibited cell spreading and resulted in a partial inhibition of compression-induced increase in matrix accumulation. Knockdown of MT1-MMP expression partially inhibited cell retraction and resulted in a reduced matrix accumulation as well. These results suggest that chondrocyte spreading and retraction following cyclic compression in vitro regulates matrix accumulation. Understanding the mechanisms that regulate chondrocyte mechanotransduction may ultimately lead to the design of improved repair tissue for cartilage damage. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.
Related Concept Videos
Cell-matrix's Response to Mechanical Forces
Anchoring junctions mechanically attach a cell to the...
Activation of Integrins
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
Intracellular Signaling Affects Focal Adhesions
Some...
Overview of Cell-Matrix Interactions
Tension Response at Adherens Junctions
α-Catenin as a Mechanosensory Protein
The α-catenin of adherens junctions is an allosteric protein with three VH (vinculin homology) domains...
Integrins
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
