AR and rheumatoid arthritis: Furthermore, based on the results of cell viability, we found RA pretreatment reduced AR-induced cell death, and the result showed the protective effect of RA started at 5 μM concentration, reached its maximum at 15 μM, and gradually decreased at 20–25 μM (Supplementary Figure S1B), which was consistent with previous research (Luan et al., 2013; Coelho et al., 2017).