utilized a PEI‐based carrier to deliver plasmid encoding TNF‐α shRNA, effectively reducing cellular the TNF‐α mRNA level to 23% in macrophages compared to that of the control group in vitro.[173] As indicated by immunohistochemistry staining, plasmid encoding TNF‐α shRNA effectively inhibited TNF‐α in collagen‐induced arthritis (CIA) mice, significantly alleviating the progression of RA. This evidence concerns the gene TNF and rheumatoid arthritis.