Hyaluronic acid modulates gene expression of connective tissue growth factor (CTGF), transforming growth factor‐β1 (TGF‐β1), and vascular endothelial growth factor (VEGF) in human fibroblast‐like synovial cells from advanced‐stage osteoarthritis in vitro

Intraarticular injection of hyaluronan (hyaluronic acid; HA) is the common way to treat osteoarthritis (OA) of knees. This treatment cannot only maintain the viscoelastic properties of knee but also release the OA pain. However, the exact molecular mechanism is unknown. In this study, after human synovial cells were stimulated with HA and Hylan (Synvisc®) for 24 h, real‐time polymerase chain reaction (real‐time PCR) was used to detect the alteration of connective tissue growth factor (CTGF), transforming growth factor‐β1 (TGF‐β1), and vascular endothelial growth factor (VEGF) gene expression, which were specific genes related to pathogenesis of OA knees. Our results illustrated that both HA and Hylan might not cause cytotoxicity or apoptosis of synovial cells in serum deprivation environment. The gene expressions of TGF‐β1 and VEGF were significantly increased at the concentration of 0.1 mg/mL HA and 0.1 mg/mL Hylan, respectively (α < 0.05). The synovial cells with treatment of 0.1 mg/mL Hylan decreased the CTGF gene expression (0.66‐fold) and VEGF (0.78‐fold) compared to 0.1 mg/mL HA (α < 0.05). We suggested that the profile of CTGF, TGF‐β1, and VEGF gene expressions in our study might provide the rational mechanism for the therapeutic effect of hyaluronan on OA knees.