Mechanical compression influences intracellular Ca2+ signaling in chondrocytes seeded in agarose constructs.
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 percent 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 Ga3+ 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.
Roberts
S R
SR
IRC in Biomedical Materials, Institute of Orthopaedics, University College London Medical School, Brockley Hill, Stanmore, Middlesex HA7 4LP, London E1 4NS, United Kingdom. ez7036@qmw.ac.uk
Knight
M M
MM
Lee
D A
DA
Bader
D L
DL
D000465:Algorithms; D000818:Animals; D020013:Calcium Signaling / Q000502:physiology*; D002417:Cattle; D002478:Cells, Cultured; D019902:Chondrocytes / Q000502:physiology*; D005110:Extracellular Space / Q000502:physiology; D007091:Image Processing, Computer-Assisted; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology; D018613:Microscopy, Confocal; D010812:Physical Stimulation; D012685:Sepharose
D012685:Sepharose