Effects of interleukin-6 on proliferation and proteoglycan metabolism in articular chondrocyte cultures

Cell Biol Int. 1998;22(9-10):615-21. doi: 10.1006/cbir.1998.0304.


Interleukin-6 (IL-6) levels are markedly increased in the synovial fluid of patients with rheumatoid arthritis or osteoarthritis. However, the effects of IL-6 on proliferation and proteoglycan metabolism in articular cartilage are not known. We demonstrated here the effects of human recombinant (hr) IL-6 on proliferation and proteoglycan metabolism in rabbit articular chondrocyte cultures. In vitro, these cells proliferated and produced abundant extracellular matrices. We found that 1-10 ng/ml of hrIL-6 inhibited proliferation to approximately 65% of control levels and suppressed colony formation induced by bFGF in soft agarose. The same concentration of hrIL-6 depressed proteoglycan synthesis to approximately 60% of control levels. Moreover, hrIL-6 significantly enhanced proteoglycan degradation induced by hrIL-1beta, although hrIL-6 alone did not affect proteoglycan degradation. These findings suggest that IL-6 is a negative regulator for chondrocyte proliferation and articular cartilage metabolism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arthritis, Rheumatoid / metabolism
  • Cartilage, Articular / cytology*
  • Cartilage, Articular / drug effects*
  • Cartilage, Articular / metabolism
  • Cell Division / drug effects
  • Cell Size
  • Cells, Cultured
  • Chondrocytes / cytology*
  • Chondrocytes / drug effects*
  • Chondrocytes / metabolism
  • Fibroblast Growth Factor 2 / pharmacology
  • Humans
  • Interleukin-6 / metabolism
  • Interleukin-6 / pharmacology*
  • Osteoarthritis / metabolism
  • Proteoglycans / metabolism*
  • Rabbits
  • Recombinant Proteins / pharmacology
  • Synovial Fluid / metabolism


  • Interleukin-6
  • Proteoglycans
  • Recombinant Proteins
  • Fibroblast Growth Factor 2