PTGS2 and inflammatory bowel disease: Additionally, in accordance with previous results from a study of DSS-induced colitis in piglets weaned at day 21 [42], we found that DSS treatment caused an increase in the expression of the pro-inflammatory cytokines IL-17A and IL-6, the pro-inflammatory enzyme PTGS2 and the chemokine IL-8 in the colon; expression of the latter is shown to be significantly higher in inflamed versus normal colonic mucosa of IBD patients [43].