Gastroprotective effect of leptin in indomethacin-induced gastric injury

This study investigated the involvement of neutrophil infiltration, disturbances in nitric oxide (NO) generation and oxidative stress in indomethacin-induced gastric ulcer, and the possible gastroprotective potentials of leptin, known for its angiogenic effect. Male Wistar albino rats (180-220 g) were allocated into a normal control group, ulcer control group (received a single dose of indomethacin 40 mg/kg p.o.) and an ulcer group pretreated with leptin (10 mu g/kg i.p. 30 min before ulcer induction). The animals were killed 6 h after indomethacin administration and their gastric juice, serum and mucosal tissue were used for gastric injury evaluation. Indomethacin produced multiple lesions in glandular mucosa, evidenced by marked increase in gastric ulcer index (GUI) accompanied by significant increases in gastric juice acidity, tissue myeloperoxidase (MPO) activity, serum NO and tissue conjugated diene (CD), and marked decreases in tissue NO and glutathione (GSH) as well as glutathione reductase (GR) and superoxide dismutase (SOD) activities, while gastric juice mucin and tissue glutathione peroxidase (GPx) were not affected. Leptin exerted significant gastroprotection as evidenced by significantly decreased GUI and attenuated neutrophil infiltration. Leptin significantly increased mucin and tissue NO, restored GR and SOD activities and up-regulated GPx activity. It failed to affect acidity, serum NO, GSH and CD. These results suggest that leptin confers significant gastroprotection against indomethacin-induced injury through interfering with neutrophil infiltration, NO production and oxidative stress.