Objective: To evaluate whether leptin has an protective effect on small intestinal damage induced by hypoxia reoxygenation in newborn rats.

Materials and Methods: There were three equal Groups each consisted of 10 newborn rats. Group 1; control, Group 2; hypoxia-reoxygenation, Group 3; leptin-hypoxia-reoxygenation. The rats of Group 3 were pretreated with leptin (20 microgram/kg) one hour before experiments then rat pubs in Group 2 and Group 3 were stressed twice daily with asphyxia followed by cold (+4º C for 10 min). Breathing 100% CO2 for ten minutes in a chamber followed 10 minutes 100% O2 breathing was the asphyxia model. This protocol was repeated for the following two days and the rat pups were decapitated on the third day. The entire gastrointestinal tract was removed. A 3-cm section of distal ileum from each animal was taken. Histopathological damage and epidermal growth factor receptors (EGFR) are evaluated. For biochemical evaluation, tissue malondialdehyde (MDA) and nitric oxide (NO) levels were measured.

Results: In Group 2 and Group 3 macroscopic intestinal injuries were observed. Histopathological grading and immunohistochemical EGFR evaluation showed similar damage in the Group 2 and the Group 3. In these Groups tissue MDA levels were also in the same ranges but NO levels were different each other with the higher levels of Group 2. Group 3 had same NO levels with control Group. Conclusions: Leptin pretreatment has no protective effect on hypoxia reoxygenation induced intestinal injury in newborn rats although it changes NO levels in the injured intestine.