缺血后处理改善脑缺血再灌注大鼠软脑膜微循环

目的:研究缺血后处理(I-postC)对脑缺血/再灌注(I/R)大鼠软脑膜微循环的改善作用及其机制。方法:32只雄性Wistar大鼠随机分为假手术(sham)、I/R、I-postC及缺血预处理(IPC)组，采用颈动脉引流法建立大鼠全脑I/R损伤模型，于实验结束时观测软脑膜微循环和脑表面血流量变化，酶联免疫吸附法测定血浆可溶性细胞间黏附分子-1(sICAM-1)含量，试剂盒测定脑组织髓过氧化酶(MPO)、超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量，免疫印记法检测脑组织血管内皮钙黏蛋白(VE-cadherin)和NF-κB p65的表达。结果:(1)I-postC明显改善微循环血流状态，减轻I/R所致的细动静脉收缩和脑表面血流量降低(均P<0.05)，且脑组织VE-cadherin量减少程度较I/R组减轻(P＜0.05)；(2)与I/R组比较，I-postC组血浆sICAM-1含量、脑组织MPO活性和MDA含量降低(P＜0.05或P＜0.01)，SOD活性增高(P＜0.05)，且脑组织NF-κB p65表达下调(P＜0.05)。结论:I-postC可改善脑I/R大鼠软脑膜微循环，其机制与抑制ICAM-1介导的中性粒细胞活化有关。

Ischemic postconditioning ameliorates pia mater microcirculation in rats subjected to cerebral ischemia reperfusion

AIM:To investigate the ameliorative effect of ischemic postconditioning (I-postC) on pia mater microcirculation in rats subjected to cerebral ischemia reperfusion (I/R) and its mechanisms.METHODS:Thirty-two male Wistar rats were randomly divided into sham, I/R, I-postC, and ischemic preconditioning (IPC) groups.The global cerebral I/R injury was induced by shunting carotid artery in rats.Pia mater microcirculation and cerebral microcirculatory perfusion were measured after reperfusion.The content of soluble intercellular adhesion molecule-1 (sICAM-1) in plasma was detected using enzyme linked-immunosorbent assay (ELISA).Myeloperoxidase (MPO), malondialdehyde (MDA), and superoxide dismutase (SOD) in cerebral tissue were detected.The expressions of vascular endothelial cell cadherin (VE-cadherin) and NF-κB p65 in cerebral tissue were assayed by Western blotting.RESULTS:(1) The disturbance of the blood flow in microvessel induced by I/R was improved significantly by I-postC.In addition, I-postC alleviated significantly the decrease in diameters of microvesseles, cerebral microcirculatory perfusion and cerebral VE-cadherin content induced by I/R (P＜0.05).(2) sICAM-1 in plasma, MPO and MDA in cerebral tissue decreased, but SOD activity in cerebral tissue increased in I-postC group, compared with those in I/R group (P＜0.05 or P＜0.01).The over-expression of NF-κB p65 induced by I/R was relieved by I-postC (P＜0.05).CONCLUSION:I-postC ameliorates pia mater microcirculation in rats subjected to cerebral I/R through suppressing the activation of polymorphonuclear neutrophils mediated by ICAM-1.