Effect of venlafaxine on experimental colitis in normal and reserpinised depressed rats

Psychological disorders such as depression have more prevalence in inflammatory bowel disease patients and can exacerbate the clinical course of the disease, so anti-depressant therapy may have a potential to positively impact the disease course. On the other hand several antidepressant drugs have shown anti-inflammatory and immunomodulatory properties. Thus, this study aimed to explore the beneficial effects of venlafaxine on experimental colitis in normal and reserpinised depressed rats. Acetic acid colitis was induced in both reserpinised and non-reserpinised rats. Reserpinised groups received reserpine at dose of 6 mg/kg i.p.1 h prior to colitis induction and then treated with venlafaxine at doses of 10, 20, 40 mg/kg given i.p. 2 h after induction of colitis and daily for 4 consecutive days. Non-reserpinised groups treated with 10, 20, 40 mg/kg venlafaxine i.p. 2 h after the induction of colitis and daily for 4 successive days. Dexamethasone (1 mg/kg, i.p.) was used as reference drug. Colonic inflammation was evaluated using macroscopic, histological and myeloperoxidase activity measurements. Results showed that reserpine at dose of 6 mg/kg exacerbated the colitis damage. Compared to acetic acid control, venlafaxine at dose of 40 mg/kg as well as dexamethasone significantly improved colitis parameters in both reserpinised and non-reserpinised animals. Venlafaxine reduced inflammatory injury in this animal model of induced ulcerative colitis. These effects are probably mediated first through depressive behavioral changes that could be mediated through the brain-gut axis and second for the anti-inflammatory effect of the drug.