SOD1 and rheumatoid arthritis: Another study conducted on a rat model demonstrated that Se-methionine-folic acid nanoparticles (SeMetFa NPs) also show potential for use in the treatment of RA due to their ability to increase the concentration of the antioxidant enzymes GPx, SOD, and CAT in the liver, kidneys, and spleen, which reduces the concentration of the inflammatory biomarkers TNF-α, CRP, and PGE2 in the serum and reduces paw joint swelling.