AdCMV.NK4 inhibits inflammatory cell infiltration, as well as cytokine and RANKL expression, in the synovial tissues of SKG mice. Immunohistochemistry of interleukin 1 (IL-1) (A), IL-6 (B), TNF-α (C), CD31 (D), IL-17 (E) and RANKL (receptor activator of nuclear factor κB ligand) (F). High-level expression of IL-1, IL-6, TNF-α, CD31, IL-17 and RANKL in the synovial tissues of LacZ-treated SKG mice was observed (upper). In contrast, the expression was significantly inhibited in the synovial tissues of NK4-treated SKG mice (lower). Original magnification, ×200.