Effect of L-arginine,aminoguanidine and agmatine on focal cerebral ischemia-reperfusion injury in rats

AIM:To investigate the protective effects of L-arginine(L-Arg),aminoguanidine(AG) and agmatine(AGM) on cerebral ischemia-reperfusion injury and to evaluate the role of NO in cerebral ischemic injury.METHODS: The suture-occluded method was used in rats to establish the animal model of middle cerebral artery occlusion(MCAO).The neurobehavioral changes were evaluated by Longa scoring.The content of NO in serum was determined with microplate reader.The activity of iNOS in the focal ischemic cerebral tissues at the scheduled time was assayed by immunohistochemical method.RESULTS: (1) Compared to sham-operation group,the NO content significantly increased(P0.05) in the MCAO rats after reperfusion for 12 h,24 h and 72 h following ischemia.(2) Compared to ischemic group,the neurobehavioral scores in L-Arg group significantly decreased(P0.05) after reperfusion for 12 h following ischemia and the NO content increased(P0.05).After reperfusion for 24 h following ischemia,the neurobehavioral scores and the NO content in both AG group and AGM group significantly decreased(P0.05).After reperfusion for 12 h,24 h and 72 h following ischemia,the iNOS-positive cells in L-Arg group had no statistical difference(P0.05),but those in AG group and AGM group was lower than those in ischemic group(P0.05) and L-Arg group(P0.05).CONCLUSION: The contents of NO in serum and expression of iNOS in the focal ischemic cerebral tissues have dynamic changes with the time course of ischemia-reperfusion injury.Administration of L-Arg,AG or AGM has beneficial effect on the animals with cerebral ischemia-reperfusion.