FOS and Arthritis: Collectively, it is reasonable to conclude that FIR may provide beneficial effects on the AIA rat model of arthritis by suppression of the MAPK, PI3K-Akt and NF-κB signaling pathways, and down-regulating of inflammatory and immunity genes through key transcription factors such as AP-1, C/EBP α, C/EBP β, c-Fos, GR, HNF-3 β, USF-1, and USF-2 (Fig. 6E).