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Calcium signaling is required for ultrasound‐stimulated aggrecan synthesis by rat chondrocytes
Author(s) -
Parvizi Javad,
Parpura Vladimir,
Greenleaf James F.,
Bolander Mark E.
Publication year - 2002
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1016/s0736-0266(01)00069-9
Subject(s) - thapsigargin , ultrasound , egta , calcium , calcium in biology , intracellular , proteoglycan , chemistry , aggrecan , stimulation , bapta , microbiology and biotechnology , biochemistry , medicine , extracellular matrix , biology , pathology , osteoarthritis , alternative medicine , organic chemistry , radiology , articular cartilage
Low‐intensity ultrasound accelerates fracture healing in humans. In rat femur fracture models, ultrasound advanced healing is associated with increased proteoglycan expression. Here we report that ultrasound stimulation of primary rat chondrocytes elevated the intracellular concentration of calciums [Ca 2+ ] i . The [Ca 2+ ] i increase was rapid and transient at lower pressures (175–320 kPa), but rapid and sustained at higher ultrasound exposures (350–500 kPa). Chelating internal [Ca 2+ ] i with 1,2‐bis(2‐aminophenoxy) ethane‐ N ‐ N ‐ N ′‐ N ′‐tetraacetic acid (BAPTA‐AM), stopping the Ca 2+ /ATP‐ase induced mitochondrial release of [Ca 2+ ] i with Thapsigargin, or removing [Ca 2+ ] i from the medium with EGTA inhibited the stimulatory effects of ultrasound on proteoglycan synthesis. These results imply that ultrasound‐stimulated synthesis of cell matrix proteoglycan, associated with accelerated fracture healing, is mediated by intracellular calcium signaling. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.