The SOD incorporated in the nanoparticles exhibited effective scavenging of O2•− and notably reduced the expression levels of various in vitro inflammation-associated cytokines (granulocyte colony-stimulating factor G-CSF, monocyte chemotactic protein-1 MCP-1 as well as regulated on activation, normal T cell expressed and secreted RANTES), which is beneficial to the treatment of RA. The gene discussed is SOD1; the disease is rheumatoid arthritis.