Effects of L-arginine on the Endotoxin Induced Lung Injury in Rats

AIM:To investigate the effects of L-arginine and nitric oxide(NO) on endotoxin induced lung injury in rats. METHOD: Thirty two healthy male SD rats weighing 300±20 g were used. Common carotid artery (CAA) and common carotid vein (CAV) were exposed. Mean arterial pressure (MAP) was measured through a pressure transducer connected with intubation of CAA. The animals were randomly divided into four groups:group 1:control;group 2:LPS (5 mg/kg intravenous injection,iv);group 3:high dose L-arginine (500 mg/kg intraperitoneal injection,ip) and group 4:low dose L-arginine (250 mg/kg ip). Group 1:0.9% saline solution was given and the animals were killed 6 h after given the saline solution. Group 2:0.9% saline solution was given 3 h after LPS iv and the animals were killed 3 h after medication. Group 3 and 4:L-arginine was given 3 h after LPS iv and the animals were killed 3 h after medication respectively. The pulmonary coefficient and water content in pulmonary tissue were calculated (%).The NO content in plasma,MDA content and NOS,SOD activity in the pulmonary tissue were measured. RESULT:L-arginine significantly decreased pulmonary coefficient and water content in pulmonary tissue and ameliorated endotoxin induced lung injury. L-arginine significantly decreased MDA content and inhibited NOS activity and enhanced SOD activity in the pulmonary tissue. CONCLUSION:It may be concluded that L-arginine has beneficial effect on lung injury induced by LPS.