Figure 4: PCA activates Nrf2/Keap1 signaling pathway in H2O2-induced RA-FLSs. The expression of proteins associated with Nrf2/Keap1 signaling pathway in H2O2-induced MH7A cells treated by PCA was detected by western blot. ***P < 0.001 versus control group. #P < 0.05 and ###P < 0.001 versus H2O2 (5 μM) group. PCA: Protocatechuic acid, RA-FLSs: Rheumatoid arthritis fibroblast-like synoviocytes.