大鼠肢端缺血预处理对脑缺血后炎症反应的影响

The Effects of Limb Ischemic Preconditioning Pretreatment on the Inflammatory Response Induced by Cerebral Ischemia in Rats

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:6 h、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12 h、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12 h、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。

Objective To investigate whether limb isehemic 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 （6 h, 12 h, 24 h, 48 h 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 d8 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,24 h and 48h 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.