TNF and Hepatic fibrosis: Analysis of liver mRNA involved in activated HSCs promoting liver fibrosis revealed that liver interleukin1 (IL-1), tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta (TGF-β), platelet-derived growth factor (PDGF), tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2 and collagen I were significantly up-regulated in iNOS−/−/HFD mice compared with iNOS+/+/HFD mice (Figure 5B).