In general, the MAPK signaling pathway can mediate the release of TNF-α, IL-1, IL-6, IL-8, and other inflammatory factors, cell apoptosis, and neutrophil activation, induce the expression of intracellular nitric oxide, improve the activity of intracellular inducible nitric oxide synthase, and induce the occurrence and development of IBD and colon cancer (Yong et al., 2009). Here, NOS2 is linked to irritable bowel syndrome.