Effects of interleukin-6 on proliferation and proteoglycan metabolism in articular chondrocyte cultures.
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.
Jikko
A
A
Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Wakisaka
T
T
Iwamoto
M
M
Hiranuma
H
H
Kato
Y
Y
Maeda
T
T
Fujishita
M
M
Fuchihata
H
H
D000818:Animals; D001172:Arthritis, Rheumatoid / Q000378:metabolism; D002358:Cartilage, Articular / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D048429:Cell Size; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism / Q000494:pharmacology*; D010003:Osteoarthritis / Q000378:metabolism; D011509:Proteoglycans / Q000378:metabolism*; D011817:Rabbits; D011994:Recombinant Proteins / Q000494:pharmacology; D013582:Synovial Fluid / Q000378:metabolism
D015850:Interleukin-6; D011509:Proteoglycans; D011994:Recombinant Proteins; D016222:Fibroblast Growth Factor 2