Mechanical compression influences intracellular Ca2+ signaling in chondrocytes
seeded in agarose constructs.
Roberts, Susan R., Martin M. Knight, David A. Lee, and Dan L. Bader.
1IRC in Biomedical Materials, Institute of Orthopaedics, University College London
Medical School, Brockley Hill, Stanmore, Middlesex HA7 4LP; 2IRC in Biomedical
Materials, Queen Mary and Westfield College, University of London, Mile End; and
3Medical Engineering Division, Department of Engineering, Queen Mary and Westfield
College, University of London, Mile End, London E1 4NS, United Kingdom
APStracts 8:0014A, 2001.
Calcium (Ca2+) signaling forms part of a possible mechanotransduction pathway by
which chondrocytes may alter their metabolism in response to mechanical loading. In this
study, a well-characterized model system utilizing bovine articular chondrocytes
embedded in 4% agarose constructs was used to investigate the effect of physiological
mechanical compressive strain applied after 1 and 3 days in culture. The intracellular
Ca2+ concentration was measured by use of the ratiometric Ca2+ indicator Indo 1-AM
and confocal microscopy. A positive Ca2+ response was defined as a percentage increase
in Ca2+ ratio above a preset threshold. A significantly greater percentage of cells
exhibited a positive Ca2+ response in strained constructs compared with unstrained
controls at both time points. In strained constructs, treatment with either gadolinium or
EGTA significantly reduced the number of positive Ca2+ responders compared with
untreated controls. These results represent an important step in understanding the
physiological role of intracellular Ca2+ in chondrocytes under mechanical compression.
Received 11 September 2000; accepted in final form 1 November 2000
APS Manuscript Number A0645-0.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 29 January 2001