Abstract: Objective To investigate the effect of melatonin on adrenaline induced experimental pneumonary edema in rabbits. Methods Eighteen rabbits were randomly divided into normal group, model group, melatonin group. In the melatonin group, rabbits were received an injection of 10 mg/kg melatonin, followed by injection of 1 mg adrenaline (AD) after 30 min. In the model group, after a corresponding bolus of normal saline, AD was administrated. Normal group were injected with a corresponding bolus of normal saline. The effect of melatonin was evaluated by light microscopy, the indications of the animals as breathing and lung index. Results In the model group, respiratory frequency and lung index were significantly higher compared with the normal group. Histopathological alterations presented hemorrhage, edema thickened alveolar septum in alveolar spaces. Melatonin decreased the respiratory frequency remarkably and lung index. Light microscopic analysis disclosed that lung were less deteriorated in the melatonin group than in the model group. Conclusion Melatonin has aprotective effect on adrenaline induced pulmonary edema.

Key words: Melatonin, Adrenaline, Pulmonary edema