Melatonin prevents ischemia - reperfusion injury following superior mesenteric artery occlusion in the rat

Abstract: Free radicals derived from molecular oxygen have been reported to be responsible for changes in motility and mucosal damages observed in intestinal Ischemia-Reperfusion (I/R) injury. Melatonin has been considered as an antioxidant that prevents injuries resulting from Ischemia/Reperfusion in various tissues. This study was designed to determine the effects of melatonin at a dose dependent manner in intestinal I/R damages by contractile responses of Malondialdehyde (MDA), a product of lipid peroxidation in rats. A total of 36 young male Wistar - Albino rats (80 - 120 g) were divided equally in to 6 groups and subjected to different concentration of melatonin (10, 20, 30 mg/Kg). Group 1 was control, group 2 was sham that were subjected to surgical process for Superior Mesenteric Artery (SMA) dissection. Groups 3, 4, 5 and 6 were I/R that were given melatonin at 0, 10, 20 and 30 mg/kg respectively. After laparatomy, a microvascular traumatic clip was placed across the SMA under general anesthesia, and following ischemia for 30 minutes it was removed. The first dose of melatonin was administrated before, and the second dose was administrated just after reperfusion, and the third dose was administrated on the second day, all by intramuscular route. On the third day of the experiment all rats were killed, and their bowels were removed. The levels of tissue malondialdehyde were found to be significantly lower in group 4 compared to group 3 (P < 0.05).There was significant differences in histopathological patterns of group 4 compared with group 3 (P < 0.01). MDA levels, in groups 5 and 6, showed no significant changes in comparison to I/R group. These results showed that Melatonin at dose of 10 mg/Kg has antioxidant effects and prevents rat intestinal ischemia - reperfusion damages.