NOS2 and colitis: Exposure to IS caused colitis; it induced colon shortening [F(1,14) = 19.243, p = 0.001] and myeloperoxidase activity [F(1,14) = 301.258, p < 0.001] and up-regulated nuclear factor (NF)-κB activation (p-p65) and cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), IL-6, TNF-α, and IL-1β expression in the colon (Figs 1n–q and S1c–h).