To study the effect of interleukin-1 (IL-1 beta) on the metabolism of osteoarthritic and normal mature condylar chondrocytes in temporomandibular joints, and investigate the role of IL-1 beta in the pathogenesis of temporomandibular joint osteoarthritis.
The primary generation of osteoarthritic and normal condylar chondrocytes cultured in the monolayer condition was treated with 20 micrograms.L-1 recombined human interleukin-1 beta (rhIL-1 beta), and then collected to be detected with RT-PCR method for the cellular metabolism including mRNA expression of type II collagen, aggrecan, collagenase, insulin-like growth factor 1 (IGF-1), and transforming growth factor beta 1 (TGF beta 1).
The normal mature condylar chondrocytes showed the obviously decreased mRNA expression of type II collagen and aggrecan after the intervention of exogenous IL-1 beta, but less influence could be found for the collagenase expression. The osteoarthritic condylar chondrocytes exhibited the decreased mRNA expression of type II collagen and collagenase under the effect of IL-1 beta, while the cellular mRNA expression of aggrecan didn't change obviously. The intervention of exogenous IL-1 beta didn't show an obvious influence on the cellular expression of endogenous growth factors such as IGF-1 or TGF-beta 1 for both the normal and osteoarthritic condylar chondrocytes cultured in vitro.
IL-1 beta could not only disturb the expression of cartilage matrix molecules by the normal condylar chondrocytes, which lead to the lesion of condylar cartilage, but also worsen the abnormal cartilage matrix environment within the osteoarthritic condylar cartilage.