Study On The Effect Of Pretreatment Of Atorvastatin On Focal Cerebral Ischemia-reperfusion Injury In SD Rats On IL-6，IL-1β And C-fos

Objective: Observe the expression of interleukin-6, interleukin-1β and c-fos in SDrats with focal cerebral ischemia reperfusion injury. Observe the effect of preventedadministration of atorvastatin in the expression of interleukin-6, interleukin-1β and c-fosin SD rats with focal cerebral ischemia reperfusion injury, explore the mechanisms ofatorvastatin in inflammatory reaction, apoptosis and other mechanism of action afterischemia reperfusion injury. To make experimental evidence of the using for preventand treat in ischemic cerebrovascular disease.Methods:90healthy male SD rats, were randomly divided into3groups:sham-operated group, control group and atorvastatin calcium pretreatment group(atorvastatin group to abbreviate), thirty rats in each group. Each group was divided into6subgroups according to reperfusion1h(n=5),2h(n=5),6h(n=5),12h(n=5),48h(n=5),72h(n=5),after ischemia for2hours. Sodium chloride solution(10ml/kg/d), Sodium chloride solution(10ml/kg/d) and atorvastatin (10mg/kg/d) wasgiven respectively to sham-operated group, ischemia-reperfusion group and atorvastatingroup by intragastric administration since the14th day before ischemia-reperfusion.Using the improved Longa-Zea method to establish ischemia-reperfusion model inright cerebral middle artery of SD rat (each group was made ischemia-reperfusionmodel except the sham-operated group). Evaluate the neurological impairment score byreferring to Zea-Longa’s standards of five grades; All removed brains was stainedrespectively with2%Tripheny1Tetrazalium Chloride(TTC); Judging the ischemiclocation, measuring the infarction pathomorphology; Observing the expression of IL-6,IL-1β and c-fos with immunohistochemical technique. Comparison:(1) Compare the difference between sham-operated group and control group inneurological impairment score, infarction volume appear, morphology of cerebral tissueand the expression of interleukine-6, interleukine-1β and c-fos.(2) Compare the difference between control group and atorvastatin group inneurological impairment score, infarction volume appear, morphology of cerebral tissueand the expression of interleukine-6, interleukine-1β and c-fos.(3) Observation the difference between the close two subgroup of control group inneurological impairment score, infarction volume appear, morphology of cerebral tissueand the expression of interleukine-6, interleukine-1β and c-fos.(4) Observation the difference between the close two subgroup of atorvastatin groupin neurological impairment score, infarction volume appear, morphology of cerebraltissue and the expression of interleukine-6, interleukine-1β and c-fos.Results:1. The neurological impairment score in control group was higher than that inthe sham-operated group at every subgroup and the result has remarkable difference(p＜0.01); neurological impairment score have no difference between the atorvastatingroup and the control group except in the group of12h,48h,72h reperfusion following2h cerebral ischemia(p＜0.05). The neurological impairment score have remarkabledifference between tne close subgroup of control group and atorvastatin group (p＜0.01), excepe1h and2h(p＜0.05).2. The infarction volume appear at2h cerebral ischemia and increased in48hafter reperfusion in the control group. The infarction volume appear at2h cerebralischemia and increased gradually in the atorvastatin group, and reached the peak at6hafter reperfusion, then it decreased gradually, but still higher than the volume ofcerebral infarction in1h, compare The infarction volume appear of control group andatorvastatin group, there are no difference execpy the subgroup of2h,6h and12havethe difference(p﹤0.05). The infarction volume showed no difference between theatorvastatin group and the control group in the subgroup of1h,2h reperfusion following2h cerebral ischemia(p>0.05).3. Morphology of cerebral tissue stained by HEThere is no infarction areas and evident pathological changes in left side of controlgroup, left side of atorvastatin group and both side of sham-operated group. In controlgroup and atorvastatin group: the number of neurons at ischemic area decreased, nerve cells shrank and degenerated, apparent edema between tissues and vacuolization. Withprolonged ischemia reperfusion, neuronal damage aggravation, irreversible injury alters,the vast majority of nerve cell necrosis, ipsilateral hippocampal region also visible partof cell shrinkage dense. The damage degree of atorvastatin group is lower than that ofcontrol group on the same subgroup.4. Immunohistology result：(1) The expression of IL-6: There is no difference between the close subgroup ofshame-operated group in tne expression of IL-6. In control group and atorvastatin groupa few of IL-6positive cells can be seen at1h cerebral ischemia in the ischemia side ofpallium tissue. It increased since6h after reperfusion and reached the peak at48h afterreperfusion, then decreased gradually. The number of IL-6positive cells in controlgroup were higher than that in sham-operated group expect the time of2h cerebralischemia(p﹤0.01); Compare with control group, the number of IL-6positive cells inatorvastatin group reduced, the difference was remarkable at reperfusion12h、48h(p﹤0.05) and72h(p﹤0.01).(2) The expression of IL-1β: In control group and atorvastatin group a few of IL-6positive cells can be seen at1h cerebral ischemia in the ischemia side of pallium tissue,there is no difference between two close subgroup of it(p>0.05). A few IL-1β positivecells can be seen since1h after ischemia-reperfusion in control group as well as theatorvastatin group. In control group, the expression of IL-1β positive cells increasedfrom1h after ischemia-reperfusion and reached the peak at12h, then decreasedgradually. In atorvastatin group, the peak of the expression of IL-1β positive cellsappear at the time of6h after schemia-reperfusion. Every sungroup of atorvastatin group,the expression of IL-1β positive cells lower than that in control group. That disparationof two group shows difference in the subgroup of2h(p﹤0.05) and remarkabledifference in the subgroup of6h and12h(p﹤0.01).(3) The expression of c-fos: A few of c-fos positive cells can be seen in cerebralcortex in every subgroup of non ischemic side in shame-operated group, control groupand atorvastatin group. There is a peak of c-fos positive cells in2h afterschemia-reperfusion in shame-operated group, that degree of increased shows differencebetween1h and2h(p﹤0.05). The expression of c-fos positive cells appear in1h andreach the peak at2h, then decreased gradually in both control group and atorvastatingroup. The expression of c-fos positive cells shows difference between every two closesubgroup in control group and atorvastatin group. At the same subgroup, the expression of c-fos positive cells in atorvastatin group is lower than that of control group, whatshows difference in6h and12h(p﹤0.05), shows remarkable difference in1h and2h(p﹤0.01).Conclusions：1. The expression of IL-6，IL-1β and c-fos were up-regulation in the progress ofischemia-reperfusion injury in SD rats.2. Prevented administration of atorvastatin could decrease the expression of IL-6，IL-1β and c-fos in SD rats.3. Prevented administration of atorvastatin could decrease focalischemia-reperfusion injury, relieve the neurological functional defect, reduce infractedvolume，the neuronal degeneration，necrosis. That significant protective effect on thecerebral ischemia-reperfusion injury might be related with the effective of statin ofholding-back the expression of IL-6，IL-1β and c-fos.