Background: Oxidative injury plays a role in the pathogenesis of inflammatory bowel disease (IBD). Oligonol, oligomerized low molecular weighted-polyphenols, have been demonstrated anti-oxidative and anti-inflammatory properties. We investigated anti-inflammatory effects of oligonol in 2 protocols of a dextran sulfate sodium (DSS)-induced colitis mouse model independently: acute colitis and repeated colitis.
Methods: DSS-induced colitis male C57BL/6 mice were made following pretreatment with different dosages of oligonol for 7 days (acute colitis model). In the second protocol, once the acute colitis had been induced with 3% DSS, sham water, oligonol (50mg/kg), and sulfasalazine (30mg/kg) were given during 2 weeks after the first DSS administration in each group. Then, 3% DSS was given again after the first DSS administration. Colitis was evaluated with macroscopic and microscopic findings.
Results: In the acute colitis model, pretreatment of 10, 50, 100mg/kg oligonol po reduced total pathologic scores significantly (p<0.05). Along with gross and pathological improvement, oligonol decreased the levels of interleukin (IL)-1, IL-6, and tumor necrosis factor-α as well as NF-κB, c-Fos, and c-Jun. Also, oligonol enhanced the expression of heme oxygenase (HO)-1 and NADH: quinone oxidoreductase-1 (NQO-1), and increased total antioxidant concentration significantly (p<0.005). In repeated colitis model, oligonol ameliorated exacerbations of colitis, whereas sulfasalazine did not (p<0.01). The level of COX-2, TNF-α were much lower, and induction of HO-1 and NQO1 were increased significantly in oligonol group, compared with in sulfasalazine group.
Conclusions: These results suggest that oligonol could be possibly protective against experimentally induced colitis through enhancing host defense mechanism. Thus, oligonol may be useful for the treatment of human IBD.