TNFSF11 and rheumatoid arthritis: To examine the actual effect of Quercetagetin on osteoclast differentiation under RA conditions as hypothesized, the CCK-8 assay was first applied to determine the viability of osteoclast precursor cells after a 48 h OIM stimulation (with or without RANKL) in the presence of indicated concentrations of Quercetagetin (1, 1.5, 2, 2.5, 3 μM).