Montelukast Efficiency in Improving the Deleterious Gastrointestinal Effects of Dexamethasone in Rats

Abstract Background: Montelukast and dexamethasone are used in combination in the treatment of asthma. Treatment by steroids resulted in gastric mucosa weakening enhancing the occurrence of ulcer in addition to its effect on the motility and contractility of gastrointestinal tract. Aim of Study: The present study was designed to evaluate the anti-ulcer effect of montelukast, a selective leukotriene (LT) D4 receptor antagonist compared to famotidine and its effect on the motility and contractility of the small intestine in gastric ulcer induced by dexamethasone and aggravated by cold stress. Material and Methods: Adult male rats were divided into 5 groups: The first received normal saline. The other groups were given dexamethasone intraperitoneally (4mg/kg/day) for 5 days. The third group received famotidine 40mg/kg/day while the fourth and fifth groups received montelukast 30 and 60mg/kg/day orally respectively thirty minutes after dexam-ethasone. At the end, rats were exposed to cold stress then sacrificed to extract the stomachs and intestines to determine gastric ulcer score and intestinal transit then the response of small intestine to acetyl choline was recorded. Then the stomachs were divided for histopathological and biochemical studies. Results: Dexamethasone treatment resulted in ulceration of gastric mucosa, increased intestinal transit, diminished intestinal contraction and increased oxidative stress. The group treated with montelukast 60mg/kg/day showed a sig-nificant decrease in mean gastric ulcer score, intestinal transit but increase of intestinal contractility. All treated groups showed significant MDA decrease, improved histopathological picture of the stomach while the two montelukast treated groups showed significant increase in SOD. Conclusion: Montelukast with high dose shows a prom-ising role in eliminating the undesirable effects induced by corticosteroids especially if associated with stress.