Objective: At the early stage of osteoarthrosis (OA) and joint damage, the cartilage cells proliferation increases dramatically, but this repair process is finally replaced by the progressive destruction of the cartilage. The reason, in accordance to the latest research, is the abnormal phenotype of the involved cartilage cell. This result suggests that the regulation of cartilage cell phenotype may be an effective way in the treatment of OA and other cartilage destructive diseases. In this study, the effects of transforming growth factor-beta(TGF-beta), insulin-like growth factor-I (IGF-I) and basic fibroblast growth factor (bFGF) on collagen expression of human mandibular condylar cartilage cells was investigated.
Methods: Chondrocytes were isolated from human fetus by enzymatic method. The second passage of the cells was used in this study. They were cultured in DMEM medium supplemented with 20% newborn calf serum (NCS). After the cells reached confluence, the medium was replaced by DMEM containing 0.4% NCS. Then the cells were exposed to different growth factors including IGF-I (10 ng/ml), TGF-beta (5 ng/ml) and bFGF (50 ng/ml). The steady state mRNA levels of different samples were examined by slot-blot hybridization. The results were analysed by Student t test.
Results: IGF-I had the least effects on the mRNA levels of three kinds of procollagen (type I, type II and type III). On the other hand, bFGF and TGF-beta could inhibit the expression of type II collagen by 0.352 and 0.685 times comparing with the control groups separately. TGF-beta increased type I collagen expression. Besides, bFGF and TGF-beta also increased the value of type I collagen/type II collagen. None of the three kinds of growth factors had obvious effects on the expression of type III collagen.
Conclusion: IGF-I can maintain the chondrocyte differentiated phenotype, while TGF-beta and bFGF have inhibitory effects.