To further prove the influence of SMAD2 on FLS-RA pyroptosis, we scanned FLSs with an electron microscope, there are fewer small pores, thinner microvilli on the cell membrane, and shorter pseudopodia in the nigericin- and LV-SMAD2-treated group than that in nigericin treated group (Fig. 3E; P<0.05). Here, SMAD2 is linked to rheumatoid arthritis.