TNF and Hepatic fibrosis: The toxic metabolite of CCl4 can activate Kupffer cells to secrete cytokines such as interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α), stimulate transforming growth factor-β (TGF-β) production, inhibit nitric oxide (NO) formation and induce inflammation and liver fibrosis [6–8].