TNF and colitis: On day 6 post-DSS treatment, when weight loss in the IBD mouse model reached its peak (15), the Tnf−/− macrophage group (KO), but not the WT macrophage group (WT), showed reduced weight loss compared with its IBD control group (DSS only, IBD ctrl) during the colitis phase, suggesting a protective effect against colitis-induced weight loss (Figure 1D).