Since the activity of PARP-1, PARP-2, and PARP-3 isoforms can be induced by DNA-damage [39], and as oxidative stress induces mucosal injury in IBD [40, 41], we tested different H2O2 concentrations (100-1000 μM) on Caco-2 monolayers. This evidence concerns the gene PARP2 and inflammatory bowel disease.