TNF and colitis: Khor et al. (2006) have reported that Nrf2-deficient mice suffer under a more severe dextran-sulfate-sodium- (DSS-)induced colitis than Nrf2+ mice which was accompanied by a decreased expression of antioxidant and phase II enzymes and an increased level of proinflammatory mediators like COX-2, iNOS, interleukin 1β (IL-1β), and tumor necrosis factor α (TNFα) [42].