TNF and colitis: Pathological changes, including inflammation of inflammatory cells (green arrow), exfoliation of epithelial cells (black arrow), crypt branching (blue arrow), decreased mucus (yellow arrow) (Figure 4D), and the higher mRNA levels of TNF-α, IL-1β, and IL-6 in the colon of the DSS-treated group (Figure 4C) were observed, indicating that DSS still induced colitis in MyD88−/− mice.