TNF and arthritic joint disease: As shown in Fig. 2, at the acute inflammatory phase of arthritis, an increase in pro-inflammatory cytokines occurred in aortas as attested by the increased mRNA expression of IL-6 (Fig. 2A), TNF-α (Fig. 2B), and CXCL-1 (the IL-8 murine equivalent) (Fig. 2C) in AIA.