大鼠肢端缺血预处理对脑缺血后炎症反应的影响

摘要

Objective To investigate whether limb ischemic preconditioning (LIP) pretreatment has protective effects to the brain after cerebral ischemic injury by investigating the effects of LIP pretreatment on anti-inflammatory response in rats. Methods Seventy-two Sprague Dawley rats were divided into 3 groups; experimental group (n =30) , ischemic group ( n = 30) and control group ( n = 12). Six samples from five timepoints (6h,12h,24h,48h and 72 h after surgical manipulation) were collected for the experimental and ischemic groups, while other twelve animals were untreated and used as controls. The models with middle cerebral artery occlusion ( MCAO) were obtained by thread blocking and the models with cerebral ischemic tolerance (IT) were obtained by LIP pretreatment. The determination of histopathological changes, real-time quantitative PCR (QTR-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to observe the expression of interleukin-17 (IL-17) and interleukin-6 ( IL-6). Results The pathological change in experimental group was not as obvious as ischemia group. The results of QRT-PCR demonstrated that the expression of IL- 17 and IL-6 were reduced significantly in experimental group. Significant different in the expression of IL-17 and IL-6 were found between ischemia and experimental groups at 12 h,24 h and 48 h time points ( P < 0. 01 ). The data of ELISA suggested that the expression of IL-17 and IL-6 were reduced obviously in experimental group. Significant different in the expression of IL-17 were found between ischemia and experimental groups at 12 h N24 h and 48 h time points ( P < 0. 05 ) , while significant different in the expression of IL-6 were at 24 h and 48 h time points (P < 0. 05 ). Conclusion LIP pretreatment could induce ischemic tolerance, probably by providing obviously anti-inflammatory effects and protective function for the followed ischemic injury.%目的 通过观察肢端缺血预处理(limb ischemic preconditioning,LIP)对大鼠脑缺血性损伤后重要炎症因子表达的影响,探讨LIP诱导的脑缺血耐受与炎症反应之间的关系.方法 选取72只SD大鼠,实验组(LIP组)30只、缺血组30只和对照组12只.实验组和缺血组设立5个时间点:6h、12 h、24 h、48 h和72 h,每点6只.通过线栓法建立大鼠大脑中动脉阻塞( middle cerebral artery occlusion,MCAO)的局灶性脑缺血模型及LIP法建立脑缺血耐受模型,采用HE观察每组大鼠的脑组织形态学改变、QRT-PCR和ELISA方法检测脑组织中炎症因子IL-17及IL-6的表达变化.结果 实验组脑组织学病理改变明显轻于缺血组.与缺血组相比:实验组的IL-17和IL-6的基因和蛋白表达在整体水平均呈下降趋势；mRNA水平提示实验组在缺血12h、24 h和48 h后脑组织中IL-17、IL-6的表达量显著减少(P＜0.01)；蛋白水平提示实验组在缺血24 h和48 h后脑组织中的IL-6以及在缺血12h、24 h和48 h后脑组织中IL-17的表达量均降低(P＜0.05).结论 LIP诱导脑缺血耐受,可以减轻脑缺血后的炎症反应,对缺血性脑损伤有一定的保护作用.