PCNA and rheumatoid arthritis: In order to further examine the mechanism by which sirt6 influences RA-FLS inflammation, proliferation and apoptosis, the expression of TNF-α, IL-1β, IL-10, IL-4, Ki67, PCNA, Bcl-2, Bax and caspase-3 in the blank, oe-sirt6-NC, oe-sirt6, sh-sirt6-NC and sh-sirt6 groups was evaluated by ELISA, RT-qPCR, western blot analysis, EDU staining and flow cytometry.