| Objective TO study the inflammatory response mechanisms of cerebral ischemia reperfusion injury and the affection of cyclophosphamide to inflammatory response mechanisms after focal cerebral ischemia-reperfusion-injury in rats. Methods In this experiment,wistar rats were randomly divided into 3 groups, which were sham operated group,saline control group and cyclophosphamide pretreament group. Cyclophosphamide was injected into abdominal cavity 5 days before cerebral ischemia-reperfusion-injury in the cyclophosphamide pretreament group.The middle cerebral artery occlusion(MCAO) model was made by suture-occluded method.After 90min MCAO following different durations of reperfusion(3h,6h,,12h,24h,48h,72h),we investigated the expression of P-selectin in the frontal and parietal cortex and basal ganglia with using immunohistochemistry.After 90min MCAO following different durations of reperfusion(3h,6h,,12h,24h,48h,72h,96h),we investigated the MPO activity in the frontal and parietal cortex and basal ganglia . The content of SOD and MDA of the ischemic frontal and parietal cortex and basal ganglia were investigated at 24 of reperfusion. Hematoxylin-eosin (HE) staining was performed to evaluate brain cell damage at 72h of reperfusion.After 90min MCAO following 72h reperfusion,TTC staining was used to calculate the cerebral infarct volume. Result (1)Expression of P-selectin was not observed in brain tissue of sham operated group rats. Expression of P-selectin was expressed on ischemic endothelium in the brain vasculature.Expression of P-selectin was expressed mainly in the ischemic frontal and parietal cortex and basal ganglia in the MCA territory. Expression of P-selectin slightly increased at 3h and peaked at 12h.The expression was diminished by 72h of reperfusion.Although expression of P-selectin was fewer in the frontal and parietal cortex and basal ganglia in cyclophosphamide pretreament group,there had no significant statistical difference between pretreament group and control group(P>0.05).(2)MPO activity was started to significantly increased after 12h of reperfusion in the frontal and parietal cortex and basal ganglia in saline control group (P<0.05).In ischemic basal ganglia,MPO activity peaked at 48h ,then gradually descended.In the frontal and parietal cortex,MPO activity peaked at 24h , and remained elevated by 96h.In cyclophosphamide pretreament group, the increase of MPO activity was completely inhibited in the ischemic frontal and parietal cortex and basal ganglia after reperfusion,there had significant statistical difference between pretreament group and control group(P<0.05).(3)At 24 of reperfusion,compared with sham operated group,the content of SOD of the ischemic frontal and parietal cortex and basal ganglia in control group was lower (P<0.05),but the content of MDA of the ischemic frontal and parietal cortex and basal ganglia in control group was higher (P<0.05).Compared with control group,the content of SOD were higher in cyclophosphamide pretreament group(P<0.05). The content of MDA were lower in cyclophosphamide pretreament group (P<0.05).(4)At 72h of reperfusion, cyclophosphamide reduced cerebral infarction volume in rats(P<0.05) and improved histopathologic examination. Conclusion (1)There are inflammation after cerebral ischemia reperfusion. P-selectin was expressed at stage of cerebral ischemia-reperfusion.After that,MPO activity started to significantly increase and peak. P-selectin make the adhesion of neutrophils and endothelial cells, roll on them. Then, neutrophils infiltrate brain.It is suggested that P-selectin and neutrophils play important roles at the stage of cerebral ischemia reperfusion.(2)Cyclophosphamide may reduced cerebral ischemia-reperfusion injure by decreasing neutrophils infiltration, the production of free radical and infarct volume,while the positive effect of cyclophosphamide may have no directly relation to the expression of P-selectin on ischemic endothelium in the brain vasculature.
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