Anti-inflammatory and antioxidant effects of thiamine in dextran sulfate-induced colitis in rats

Objective: In the etiopathogenesis of inflammatory bowel disease (IBD), inflammatory and oxidative stress induced factors involved as well as genetic factors. Thiamine is known to have effects such as alleviating oxidative stress and supression of inflamation. In our study we aimed that to evaluate the antiinflammatory and antioxidant activity of thiamine in dekstran sülfat sodyum (DSS)- induced colitis in rats. Methods: Six to eight week old male Wistar Albino rats were randomly divided to four groups: Control group (n: 7), DSS group (n: 7), thiamine group (n: 7), DSS+ thiamine group (n: 7). The colitis model was induced by adding 3% DSS drinking water for seven days. Thiamine administration was applied to the thiamine group and DSS+ thiamine group for 21 days at two doses of 600 mg/kg/dose by oral gavage from the eigth day of experiment. All rats were examined for stool consistency, macroscobic hemorrhage, rectal edema and body weight measured daily. Disease activity index (DAI) was calculated and recorded daily. At 28 days, all rats were sacrificed under ether anesthesia, the spleen weight, the colon length and the colon weight were measured. Colon and rectum tissues were examined histopathologically and malondialdehyde (MDA), glutathione (GSH), tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) levels were measured. Results: In DSS+ thiamine group, it was seen that the DAI score was decreased earlier, rectal edema, rectal bleeding and diarrhea times were shorter, weight gain started earlier and weight gain was higher then DSS group at the end of the experiment. There was no increase in DAI score in thiamine and control groups. This suggests that thiamine has possitive effects on clinical findings of colitis. Histological damage to the colon tissues was observed in the DSS administered groups when damage was not observed in the control and thiamine groups. In DSS+ thiamine group, epithelial cell damage, crypt loss and goblet cell loss were less than DSS group in the colon tissue. In the DSS+ thiamine group, no congestion was observed in colon tissue compared to the DSS group, and inflammatory cell infiltration was found to be significantly less than in the DSS group. In the DSS+ thiamine group, IL-6 and TNF-α immunoreactivity was found to be decreased compared to the DSS group. This suggests that thiamine has antiinflammatory activity in the colitis model formed in rats. In the DSS+ thiamine group, the MDA level is decreased compared to the DSS group, and the GSH and GPx levels are increased. This suggests that thiamine is an antioxidant activity in the colitis model formed in rats. Conclusion: This is the first study to show that the antioxidant and antiinflammatory activity of thiamine in an experimental colitis model. Our results demostrates that thiamine has an antiinflammatory and antioxidant activity in colitis model. There is a need for experimental and clinical researchs in this area. Keywords: Thiamine, Inflammatory bowel disease, Dextran sulfate sodium, Animal Model