Potential Anti-Inflammatory Effect of Escitalopram in Iodoacetamide-Induced Colitis in Depressed Ovariectomized Rats: Role of α7-nAChR

Escitalopram, a drug of choice in the treatment of depression, was recently shown to possess an anti-inflammatory activity. The aim of the present study was to elucidate the effect of escitalopram on peripheral inflammatory cascades in iodoacetamide-induced colitis associated with depressive behavior in ovariectomized rats. Moreover, the role of α-7 nicotinic acetylcholine receptor in mediating the anti-colitic effect of escitalopram was examined using a nicotinic receptor antagonist methyllycaconitine citrate. Colitis was induced by intracolonic injection of 4% iodoacetamide in ovariectomized rats. Escitalopram (10 mg/kg/day, i.p.) was then injected for 1 week and several parameters including macroscopic (colon mass index and ulcerative area), microscopic (histopathology and scoring), and biochemical (myeloperoxidase and tumor necrosis factor-α) were determined. Colitis induction in ovariectomized rats resulted in a marked increase in colon mass index, ulcerative area, histopathological scoring, myeloperoxidase activity and tumor necrosis factor-α levels. These effects were ameliorated by escitalopram, even in the presence of methyllycaconitine indicating that α-7 nicotinic acetylcholine receptor does not mediate the anti-inflammatory effect of escitalopram. The present study revealed the beneficial effect of escitalopram in iodoacetamide induced colitis in ovariectomized rats and suggests that it may represent a new therapeutic agent for the treatment of inflammatory bowel disease, especially in patients with or at high risk of depressive behavior.