Protective Effect of L-Arginine on the Rabbit Lung Injuried by Ischemia/Reperfusion

Objective To probe into the effect of L-arginine on the rabbit lung injured by ischemia/reperfusion. Methods Thirty male rabbits were randomly divided into three equal groups: the sham operation group(group S),ischemia-reperfusion group(group IR) and L-arginine + ischemia-reperfusion group(group L-Arg+IR).Rabbits of the L-Arg+IR group were given each an IV injection of 100 mg·kg-1 of L-arginine.A model of ischemia-reperfusion injury of the left lung was then set up in each of the rabbits of group IR and group L-Arg+IR group by clamping(60 min) and declamping(60 min) of the hilus of the left lung under IV urethan anesthesia and mechanical ventilation.The same operation was performed on each of the animals of group S except for that the hilus of the left lung was not subjected to clamping/declaming.Venous blood samples from each of the rabbits of the 3 groups were taken before the operation,at the termination of ischemia(group IR and group L-Arg+IR) or 60 min after the operation(group S) and at the termination of reperfusion(group IR and group L-Arg+IR) or 120 min after the operation(group S),respectively,for the determination of the activity of plasma superoxide dismutase(SOD),content of plasma malonyldialdehyde(MDA),nitric oxide(NO)and calcitonin gene-related peptide(CGRP). Results At the termination of ischemia and reperfusion, the activity of SOD and content of NO in rabbits of the L-Arg+IR group were significantly higher than those in animals of group S or group IR(P0.01,P0.01),while the activity of SOD and content of NO were significantly lower in rabbits of group IR than those in animals of group S(P0.05,P0.05).At the termination of reperfusion,the content of MDA in rabbits of group IR was obviously higher than that in those of group S and group Larg+IR while the content of CGRP was significantly lower than that in rabbits of group S and group L-Arg+IR(P0.01,P0.01). Conclusion L-Arginine was shown to exert a protective effect on the lung submitted to an ischemia-reperfusion injury in rabbits probably by inducing the activity of SOD and increased production of CGRP.