氟比洛芬酯预处理对脑缺血-再灌注损伤大鼠COX-2表达影响

Preconditioning of flurbiprofen axetil on expression of COX-2 in rats with cerebral ischemia reperfusion injury

目的探讨氟比洛芬酯(FA)预处理对局灶性脑缺血-再灌注(I-R)损伤大鼠的脑保护效应及其对大脑皮质中环氧合酶2(COX-2)表达的影响。方法将32只雄性SD大鼠随机分为I-R组、预处理1 d组、预处理3 d组和预处理5 d组,每组各8只。进行预处理的3组大鼠在脑缺血前分别经尾静脉给予FA 20 mg/kg于1、3、5 d预处理,建立大脑中动脉阻塞(MCAO)模型,观察各组大鼠I-R损伤后24 h神经缺陷评估(NDS);2,3,5-氯化三苯四氮唑染色计算脑梗死容积百分率(BIVP)。将20只雄性SD大鼠随机分为对照组(CON组)、单纯FA给药组(FA20'组)、I-R组和FA 20 mg/kg预处理组(FA20组)每组各5只。FA20'组为经静脉单次给予FA 20 mg/kg而不建立MCAO模型;FA20组为在脑缺血前6 h,经静脉给予FA 20 mg/kg,然后建立MCAO模型,I-R损伤后24 h制作冰冻切片,进行免疫组织化学染色。结果与I-R组比较,预处理1 d组、预处理3 d组和预处理5 d组I-R损伤后24 h的NDS评分均有明显改善(P<0.05),BIVP明显缩小(P<0.05);FA重复3次预处理的脑保护效应达峰值,优于预处理1 d组(P<0.05)。I-R组COX-2阳性细胞反应强度明显高于CON组和FA20'组(P<0.05);给予FA预处理后,FA20组的COX-2免疫反应强度明显减弱,阳性细胞数大幅减少,但与CON组、FA20'组相比较,阳性细胞数仍然较高(P<0.05)。结论 FA重复预处理的脑保护效应要优于FA单次预处理,且重复3 d预处理的脑保护效果达到峰值;FA预处理是通过抑制大脑皮质中COX-2的过度表达,实现脑I-R损伤的保护作用。

Objective To investigate the brain protective effect and the expression of cyclooxygenase-2 （COX-2） in cerebral cortex of flurbiprofen axetil （FA）preconditioning on focal cerebral ischemical-reperfusion （I-R）injury in rats. Methods Thirty-two male SD rats were randomly divided into 4 groups, which were I-R, PC-1 day, PC-3 days and PC-5 days groups with 8 rats in each group. Intravenous FA 20 mg/＇kg in the last 3 groups was given for 1 day,3 days and 5 days,respective- ly, before the establishment of cerebral I-R model by meddle artery occlusion（MAOC）. The neurologic deficit score（NDS） was measured by Garcia scoring at 24 hours after I-R. The brain infarct volume percentage（BIVP） was then assessed after 1% TTC staining following the last neurological outcome evaluation. Twenty male SD rats were randomly divided into 4 groups,which were CON,FA 20＇ ,I-R and FA 20 groups with 5 rats in each group. In the FA 20＇group, the dose of FA 20 mg/kg was intravenously administered ,while MCAO model was not made. In the FA20 group, the dose of FA 20 mg/kg was intravenously administered at 6 hours before cerebral ischemia, MCAO model was made, the frozen section was made at 24 hours after I-R and done for immunohistochemistry stain. Results The NDS in PC-1 day, PC-3 days and PC-5 daysgroups at 24 h after I-R were not only greatly higher than that in I-R group （ P 〈 0. 05 ）, BIVP reduced significantly than that in I-R group （P 〈 0.05 ）. Moreover, the brain protective effect by FA repetitional preconditioning in PC-3 days group was better than that in PC-1 day group （P 〈 0. 05）, and it reached the peak value. The response intensity of COX-2 positive cells in I-R group was significantly higher than that in CON group and FA20＇group（ P 〈 0. 05 ）. The response intensity of COX-2 in FA20 group was significantly weaker, and its number of positive cells was greatly diminished comparing with that in I-R group （P 〈 0.05 ） , while compared with the CON group and FA20＇group, the number of positive cells remained high （P 〈 0. 05）. Conclusion The brain protective effect by FA repetitional preconditioning is better than that by FA single preconditioning, and it reaches the peak value when repetitional preconditioning is for 3 days ; to realize the protection of cer- ebral ischemia-reperfusion injury by FA repetitional preconditioning would pass through by inhibiting over-expression of COX-2 in cerebral cortex after focal cerebral ischemia-reperfusion injury in rats.