Fibroblast growth factor-18 promotes chondrocyte differentiation and plays a protective role in osteoarthritis

Background: Fibroblast growth factor18 (FGF18) is a synthetic growth factor that is associated with osteogenesis, chondrogenesis and articular cartilage repair. However, the exact mechanism is still unknown. In this work, we investigated the specific effects of FGF18 on chondrocyte differentiation and osteoarthritis (OA) development. Methods Recombinant FGF18 adenovirus (Ad-FGF18) was constructed to achieve instantaneous efficient expression. Chondrocyte progenitor cells were infected with Ad-FGF18 and subjected to chondrocyte differentiation. Alcian blue staining and chondrocyte differentiation markers’ qRT-PCR were used to evaluate the status of chondrocyte differentiation. Destabilization of the medial meniscus (DMM) surgery was used to construct the OA model. Ad-GFP or Ad-FGF18 was intra-articular injected once a week for 6 weeks. The knee joints were harvested for histological examination. Results FGF18 promoted chondrocyte differentiation by increasing the expression of Sox6 , Col2 (Collagen type Ⅱ) and Acan (Aggrecan). In the knee joint of Ad-FGF18 intra-articular injected, there was little cartilage degradation, increased protein levels of COL2 and ACAN, and decreased protein levels of ADAMTS5 (a disintegrin and metallopeptidase with thrombospondin type 1 motif 5) and MMP13 (matrix metalloproteinase 13). Conclusions Our findings reveal that FGF18 promotes the differentiation of chondrocytes and protects articular cartilage from degradation during OA development. This finding provides a potential novel therapeutic approach for cartilage regeneration and treatment of osteoarthritis.