Effects of endotoxin preconditioning on NOS activity in rat brain after global brain ischemia/reperfusion / 第三军医大学学报

ABSTRACT

Objective To determine the effects and significance of endotoxin preconditioning on iNOS activity,nNOS activity in rat cerebral cortex,hippocampus and cerebella region after global brain ischemia/reperfusion.Methods Global ischemia for 20 min was made by four-vessel occlusion model(4-vo) in 60 Wistar rats,among which 30 were injected of 20 ?g/kg MPL through caudal vein 24 h before model establishment.Another 8 rats undergoing sham operation served as controls.The dynamic change of iNOS activity,nNOS activity and neuron density of the cerebral cortex,hippocampus and cerebella region were observed at 1,4,8 h after reperfusion. Results The activity of iNOS and nNOS decreased significantly after endotoxin preconditioning in the regions mentioned above,as compared with that of rats only undergoing the ischemia/reperfusion.The neuron number in rat hippocampus decreased after ischemia/reperfusion,but no significant difference was found between control and endotoxin preconditioning groups.Conclusion The activity of iNOS and nNOS changed significantly after global brain ischemia/reperfusion.That endotoxin preconditioning decreased iNOS and nNOS activities may be the protective mechanism.