Regular Article
Nitric oxide in osteoarthritis

https://doi.org/10.1053/joca.1998.0216Get rights and content
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Abstract

Activated articular chondrocytes produce large amounts of nitric oxide (NO), and there is increasing evidence that this is involved in the etiopathogenesis of osteoarthritis (OA). Because of its short half-life, the biological effects of endogenously produced NO are likely to occur locally within the cartilage. We have observed that inhibitors of NO synthases relieve the inhibition of matrix synthesis that otherwise occurs in response to IL-1. To avoid the use of inhibitors, we have recently transduced chondrocytes with the iNOS (NOS-2) gene and confirmed the ability of the endogenously produced NO to inhibit matrix synthesis. Despite the high levels of NO made by these cells, there was no evidence of apoptosis or other forms of cell death. NO was also shown to inhibit the production of TGF-β1by cells treated with IL-1, as well as to decrease matrix production in response to IGF-1. The hypothesis that NO inhibits matrix production by interfering with important autocrine and paracrine factors should be entertained.

Keywords

NO, Osteoarthritis, Cartilage

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Corresponding author: C. H. Evans, Ph.D., D.Sc., University of Pittsburgh School of Medicine, 200 Lothrop Street, Rm. C-313 PUH, Pittsburgh, PA 15213. Tel: (412) 648-1092; Fax: (412) 648-8412; E-mail:[email protected]