Changes of nitric oxide,superoxide dismutase and malondialdehyde in the blood and brain of rats during cerebral ischemia

Objective To study the changes of nitric oxide(NO),superoxide dismutase (SOD) and malondialdehyde(MDA) in the blood and brain of rats during cerebral ischemia and their action mechanisms. Methods 46 Wistar rats were randomly divided into the ischemia and control groups.The ischemia model of rats was established by bilateral ligation of common carotid artery and the control group of rats was given sham operation.The No,SOD and MDA concentrations in the blood serum and different regions of the brain were measured in both control and ischemia groups at 10,30,60,180 and 360 min after the operation. Results In the ischemia groups,NO concentrations of the serum and brain tissue were significantly increased at 10,30 and 60 min as compared with that before the operation(P001 and P0001).The No concentrations in the serum and brain tissue of the ischemia rats began to increase within 10 min after the onset of cerebral ischemia and were highest at 30 min and then returned to the same level as that of 10 min at 60 min.However,at 180 min,the No level was the lowerst;then 360 min,it elevated again and was slightly higher than that of the control group(P005).Significantly low SOD activity and high MDA level were observed in the ischemia group at 360 min.Conclusions The longer the ischemia,the lower the SOD activity and the higher the MDA content will be.The excessive production of NO which participates in lipid peroxidiation,might be cytotoxic and neurotoxic,is deleterious to the cerebral cells and brain function.