Figure 11.

Schematic representation of the differentially expressed genes and how they are induced upon injection by (A) pristane or (B) phytol. The molecular pathway that is shared between the arthritis resistant DA.Ncf1^E3 rat strain and the arthritis treatment achieved with phytol is the Ifn-β-dependent pathway, which results in the upregulation of Best5, Irf7, Ifit3, Oas1 and Mx2. The inflammatory arthritis that is induced by an injection with pristane is characterized by increased expression of the Ifnγ-connected signature genes Ass, Cxcl9 and Mmp12, which potentially could be used as molecular markers for an initiating inflammatory response. As this pathway is also induced by pristane in the DA.Ncf1^E3 strain this upregulation per se does not cause arthritis. Most important in this mechanism is how administration of phytol induces arthritis protection via the Ifn-β-regulated pathway in the arthritis-susceptible DA rats.