Protective Effect Of Monoclonal Antibody Against Interleukin-8 On Cerebral Ischemia-reperfusion Injury In Rats And Its Possible Mechanisms

Aim : To study the change of the interleukin-8 (IL-8) content in bloodand cerebrum after cerebral ischemia-reperfusion(IR) injury.To observethe apoptosis on cerebral ischemia-reperfusion injury. To explore theprotective effect of monoclonal antibody against IL-8 (IL-8 mAb )oncerebral IR injury in rats and its possible mechanisms.Methods :Rats'cerebral IR injury model was established by Zea Longa'sthread method. The rats were randomly divided into the differentgroups.The content of IL-8 in blood serum and brain tissue was detectedby double antibody sandwich enzyme-linked immunosorbent assay. Tunelstaining ,immunohistocheistry method and electronic microscope were usedto observe apoptosis on cerebral IR injury in rats. Then administered withPBS, IL-8 mAb(0.5ug,1ug and 2ug) was centrally through lateral ventricle0.5h post MCAO. Observe the change of neutrophils infiltration by HEstains ; the ischemic area was measured after TTC stains ;immunohistocheistry and TUNEL method were used to observed the expressionof bcl-2,Bax positive cells and apoptosis cells.Results : 1 ,The content of IL-8 in blood serum was increasedsignificantly at 3h after reperfusion(p<0.01),and then went down.Itreached the lever of the control group at 24h after reperfusion.Theconcentration of IL-8 in brain tissue was peaked at 6h after reperfusion( p<0.01 ) ,went down after 12h reperfusion.Moreover,there is nodifference between the group of 6h after reperfusion and 12h afterreperfusion(p>0.05).2,In IR rat model group,TUNEL positive cellincreased (p<0.05),bcl-2 and Bax immunoreative neurons increasedsingnificantly (p<0.01);the ratio of bcl-2/Bax was decreased (p<0.01);electronic microscope showed the changes of apoptosis at the early phasein these neurons.3 ,Compared with PBS group,the infiltration ofneutrophils and infarct volume reduction was found in IL-8 mAb 1ug groupand IL-8 mAb 2ug group(p<0.05and p<0.01);bcl-2 positive cells weresignificantly increased(p<0.01),Bax positive cells were significantlydecreased(p<0.01), the ratio of bcl-2/Bax was increased (p<0.01)inIL-8 mAb 1ug group and IL-8 mAb 2ug group;morethen,TUNEL positive cellswere decreased (p<0.01)in IL-8 mAb 1ug group and IL-8 mAb 2ug group. Conclusions: 1 IL-8 increased in the early time of cerebral ischemia-reperfusioninjury in rats,showing it was involved in the pathophysiological courseof cerebral ischemia-reperfusion injury. 2 Cerebral ischemia-reperfusion injury have the important relationwith apoptosis , TUNEL positive cell increased, the ratio of bcl-2/Baxdecreased can accelerate apoptosis. 3 IL-8mAb have the blocking effect against neutrophils infliltration ,which can reduce inflammatory injury in ischemic brain tissue , regulatebcl-2,Bax gene expression, increase the the ratio of bcl-2/Bax,reduceapoptosis and infarct volume ,then achieve the protective effect oncerebral ischemia-reperfusion injury in rats.