Objective: To observe the effect of Fengshiqing (FSQ) on osteoclast differentiation of RAW264.7 cells induced by receptor activator for nuclear factor-κB ligand

RANKL(RANKL) and the secretion of bone-related immune factor tumor necrosis factor-α(TNF-α)

interleukin-17(IL-17) in RAW264.7 cells. Method: RAW264.7 cells induced by RANKL were cultured with three variable volume fraction (5%

10%

15%) of serum containing FSQ in vitro 6 days. The influence of FSQ on osteoclast (RAW264.7 induced by RANKL) differentiation was observed by tartrate-resistant acid phosphatase(TRAP) staining. RAW264.7 cells induced by IL-1β were cultured with three variable volume fraction of serum containing FSQ in vitro 24 hours

level of TNF-α

IL-17 in cell culture supernatant was examined by ELISA. Result: RANKL could induce RAW264.7 cell to form TRAP positive multinucleated cells

IL-1β could induce abnormally high expression of TNF-α and IL-17 in RAW264.7 cells. Variable volume fraction (5%

10%

15%) of serum containing FSQ could decrease the number of TRAP-positive cells dose-dependently. In addition

FSQ (10%

15%) also suppressed the expression of IL-17(P<0.01) and TNF-α (P<0.05). Conclusion: FSQ has notable inhibiting effect on osteoclast differentiation of preosteoclast cells and suppressing expression of IL-17 and TNF-α in RAW264.7 cells induced by IL-1β

which may be a part of the mechanism of FSQ for treating rheumatoid arthritis.