TNF and Arthritis: As is known, ulcerative colitis has not only intestinal symptoms, but also some extraintestinal manifestations, such as arthritis, sacroiliitis, decreased hemoglobin, etc. Our study also confirmed the enhancement of systemic inflammation (e.g., WBC, neutrophils, interleukin (IL)-17A, IL-6, interferon-γ, tumor necrosis factor-α in the serum) in DSS-induced mice.