Expression of interleukin-6 in osteoarthritic chondrocytes and effects of fluid-induced shear on this expression in normal human chondrocytes in vitro

✍ Scribed by M. Mohtai; M. K. Gupta; B. Donlon; B. Ellison; J. Cooke; G. Gibbons; D. J. Schurman; R. Lane Smith

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 773 KB
• Volume: 14
• Category: Article
• ISSN: 0736-0266
• DOI: 10.1002/jor.1100140112

✦ Synopsis

This study tested the effect of fluid-induced shear on interleukin-6 expression in normal human articular chondrocytes in vitro. As determined by Northern blot analysis, interleukin-6 mRNA expression occurs in chondrocytes from osteoarthritic cartilage but not in normal chondrocytes. Applying fluid-induced shear stress to primary high density cultures of chondrocytes increased interleukin-6 mRNA signal 4-fold at 1 hour and 10 to 15-fold at 48 hours compared with unsheared control cultures. At 48 hours, fluid-induced shear stress increased interleukin-6 protein levels in the culture medium 9 to 10-fold compared with unsheared controls. mRNA signals for interleukin-1alpha, interleukin-1beta, and tumor necrosis factor-alpha in RNA from sheared or control chondrocytes were not detected by Northern blotting. Transforming growth factor-beta mRNA signal was detectable but was not affected by shear. In contrast, human lung fibroblasts (WI-38) responded to fluid-induced shear with increased signal for transforming growth factor-beta, but not interleukin-6, mRNA. Both cell types did respond to interleukin-1alpha with increased interleukin-6 mRNA signal. These data demonstrated that distortional forces, such as fluid-induced shear stress, alter interleukin-6 levels in normal chondrocytes in vitro and suggest that increased interleukin-6 expression in osteoarthritic cartilage may result, in part, from alterations in the mechanical loading of the tissue.