Introduction: Trinitrobenzenesulfonic acid (TNBS)-induced experimental colitis in animals is a commonly used model of inflammatory bowel disease (IBD). Eugenol (Eug) is a natural phenolic compound possessing promising antioxidant and anti-inflammatory therapeutic properties.
Aim: The present study investigated the effects of Eug in a TNBS-induced rat colitis model using criteria for histopathological evaluation of the colonic damage.
Materials and methods: Male Wistar rats were divided into 6 experimental groups, each of 10 rats: Control, TNBS, TNBS+Eug1, TNBS+Eug5, TNBS+Eug25, and TNBS+Eug125 group. Eug or the solvent (sunflower oil) was applied orally using an orogastric cannula. The control group and TNBS group were treated only with sunflower oil. Eug groups were treated with corresponding doses of Eug (1, 5, 25 and 125 mg/kg) dissolved in sunflower oil. Colitis was induced by the application of TNBS in the colon. The animal treatment began 6 days before the colitis induction and continued for 8 days after it. At the end of the experiment, colitis severity was evaluated histopathologically regarding epithelium injury, inflammatory cell infiltration, and formation of granulation tissue.
Results: In all TNBS+Eug groups, the formation of granulation tissue was enhanced compared to TNBS. In group TNBS+Eug125 the difference was significant compared to the control group (p < 0.05). No significant improvement regarding the scores of epithelium injury and inflammatory cell infiltration was observed in Eug groups compared to TNBS group.
Conclusion: Eug did not improve the signs of TNBS-induced epithelial injury and inflammatory cell infiltration, but stimulated the formation of granulation tissue which might be considered as a sign of healing.
