Ameliorative effect of pyrrolidinedithiocarbamate on acetic acid-induced colitis in rats

Ulcerative colitis is a chronically recurrent inflammatory bowel disease of unknown origin. The present study examined the effect of NF-kappaB inhibitor and antioxidant, pyrrolidinedithiocarbamate (PDTC) on experimental ulcerative colitis in rats. Animals were randomly divided into 4 groups, each consisting of 6 animals; normal control group, acetic acid group, PDTC-treated group and sulfasalazine-treated group as a positive control group. Induction of colitis by intracolonic administration of 3% acetic acid produced severe macroscopic inflammation in the colon 24 h after acetic acid administration as assessed by the colonic damage score. Microscopically, colonic tissues showed ulceration, oedema and inflammatory cells infiltration. Biochemical studies revealed increased serum levels of lactate dehydrogenase (LDH), and nitrite/nitrate and colonic concentrations of tumor necrosis factor-alpha (TNF-alpha) and the neutrophil infiltration index, myeloperoxidase (MPO). Oxidative stress was indicated by elevated lipid peroxides formation and depleted reduced glutathione concentrations (GSH) in colonic tissues. Immunohistochemical studies of colonic sections revealed upregulation of inducible nitric oxide synthase (iNOS). Pretreatment with PDTC at a dose of (200 mg/kg/day, i.p.), three days before induction of colitis decreased serum LDH, nitrite/nitrate and TNF-alpha levels, colonic concentrations of MPO and lipid peroxides while increased colonic GSH concentration. Moreover, PDTC pretreatment attenuated colonic iNOS expression. Finally, histopathological changes were nearly restored by PDTC pretreatment. The findings of the present study provide evidence that PDTC may be beneficial in patients with inflammatory bowel disease.