Transient exposure of fibroblast growth factor-2 induced proliferative but not destructive changes in mouse knee joints

Fibroblast growth factor-2 (FGF-2) has the potential to regenerate damaged articular cartilage tissue due to its exerting anabolic effects on chondrocytes. However, FGF-2 is involved in pathogenesis of rheumatoid arthritis, where the joint is destructed. The study aims at clarifying the effects of FGF-2 on joints. When radiolabeled FGF-2 was injected into knee joints of C57Bl/10 mice, a transient binding was observed in the superficial and intermediate zones of the articular cartilage as well as in the synovium and perichondrium. An FGF-2 injection (5 mu g) caused synovial hyperplasia adjacent to the articular cartilage on day 7, cartilage formation adjacent to the articular cartilage on day 14, and osteophyte on day 21. The intensity of safranin-O staining of the articular cartilage increased on day 14. These changes were dose-dependent. No destructive changes in the joints were observed. In a joint, transient exposure of FGF-2 caused proliferative changes, but not destructive changes.