PTGS2 and colitis: In the potential mechanisms for colitis, the NF-KB Signal transduction pathway and inflammatory mediators, including reactive oxygen species (ROS) and cytokines, such as interleukin-1β (IL-1β),inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), produced by macrophages or epithelial cells, have been shown to contribute to the pathophysiology of colitis, especially in modulating the immune system of UC in the inflammatory cascade[26–28].