TNF and colitis: We also evaluated the mRNA levels of proinflammatory cytokines within the intestinal epithelium and found increased expression of Nos2, Il1b, and Tnf in both DSS treatment groups as compared to their respective controls, but decreased expression of Il1 and Tnf in the DSS+NR group as compared to the DSS+Vehicle group, indicating that NR treatment did alleviate inflammation during experimental colitis (Figure 3F).