- Fermor, B. and Brice Weinberg, J. and Pisetsky, D.S. and Misukonis, M.A. and Banes, A.J. and Guilak, F., The effects of static and intermittent compression on nitric oxide production in articular cartilage explants,
Journal of Orthopaedic Research, vol. 19 no. 4
pp. 729 - 737 [S0736-0266(00)00049-8] .
(last updated on 2007/04/15)
Nitric oxide (NO) production and NO synthase (NOS) expression are increased in osteoarthritis and rheumatoid arthritis, suggesting that NO may play a role in the destruction of articular cartilage. To test the hypothesis that mechanical stress may increase NO production by chondrocytes, we measured the effects of physiological levels of static and intermittent compression on NOS activity, NO production, and NOS antigen expression by porcine articular cartilage explants. Static compression significantly increased NO production at 0.1 MPa stress for 24 h (P less than or equal 0.05). Intermittent compression at 0.5 Hz for 6 h followed by 18 h recovery also increased NO production and NOS activity at 1.0 MPa stress (P less than or equal 0.05). Intermittent compression at 0.5 Hz for 24 h at a magnitude of 0.1 or 0.5 MPa caused an increase in NO production and NOS activity (P less than or equal 0.05). Immunoblot analysis showed stress-induced upregulation of NOS2, but not NOS1 or NOS3. There was no loss in cell viability following any of the loading regimens. Addition of 2 mM 1400 W (a specific NOS2 inhibitor) reduced NO production by 51% with no loss of cell viability. These findings indicate that NO production by chondrocytes is influenced by mechanical compression in vitro and suggest that biomechanical factors may in part regulate NO production in vivo. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.