A new strategy for brain protection during circulatory arrest

目的：最近的研究报道核因子-kappaB(NF-κB)的顺式元件诱骗寡核苷酸(ODN)可阻断介导缺血性损伤的基因的激活。为改善心脏手术停循环期间的脑保护，评价核因子-κB诱骗寡核苷酸对全脑缺血后神经元损伤的保护作用。方法：采用大鼠全脑缺血20min，经颈动脉注射日本血凝病毒-脂质体-FITC标记的核因子-κB诱骗寡核苷酸，评价其对脑缺血再灌注损伤的保护作用。采用实时定量聚合酶链式反应(PCR)方法检测再灌注1h后大鼠海马区与缺血再灌注损伤相关的几种因子的基因表达水平。用原位末端标记法和免疫组织化学方法检测大鼠全脑缺血后7d海马区CA-1区微管相关蛋白2(MAP2)的表达。结果：在大鼠全脑缺血过程中，通过颈动脉途径将NF-κB诱骗寡核苷酸导入大鼠脑神经元，效果显著。聚合酶链式反应结果显示，转染的NF-κB诱骗寡核苷酸能有效抑制大鼠全脑缺血1h后肿瘤坏死因子-α、白介素1-α和细胞内黏附分子-1β的表达。TUNEL染色和MAP2免疫组织化学结果显示，转染的NF-κB诱骗寡核苷酸可显著减轻大鼠全脑缺血7d后神经元的损伤。结论：脑缺血时治疗性转导NF-κB诱骗寡核苷酸可能有助于减轻神经元损伤，为全脑缺血脑保护提供了一种新的策略。

Objectives : Recent studies have reported that cis element decoy oligodeoxynucleotides (ODNs) against nuclear factor-kappa B (NF-κB) block the activation of genes that mediate ischemic injury. To improve brain protection during circulatory arrest in cardiac surgery, we evaluated the efficacy of NF-κB decoy ODNs in preventing neuronal damage after global brain ischemia.Methods : Hemagglutinating virus of Japan (HVJ)-liposome complex with FITC-labeled NF-κB decoy ODNs was injected via the carotid artery during 20 minutes of global brain ischemia in rats, to evaluate the efficacy of transfecting the decoy ODNs. The mRNA levels of several factors related to ischemic-reperfusion injury in the hippocampus were estimated using a real-time polymerase chain reaction (PCR) method 1-hour after reperfusion. Neuronal damage was evaluated by TUNEL staining and by immunohistochemical study of microtubule-associated protein 2 (MAP2) in the hippocampus CA-1 region seven days after ischemia.Results : Introduction of the NF-κB decoy ODNs into rat brain neurons via the carotid artery during global brain ischemia was markedly successful. The PCR study showed that the transfected NF-κB decoy ODNs effectively inhibited the expression of tumor necrosis factor-α (TNF-α), interleukin-1 β (IL-1 β), and intracellular adhesion molecule-1 (ICAM-1) mRNA 1 hour after global brain ischemia. TUNEL staining and MAP2 immunohistochemistry showed that the transfected NF-κB decoy ODNs significantly attenuated the neuronal damage seven days after global brain ischemia.Conclusions : Therapeutic transfection of NF-κB decoy ODNs during brain ischemia may be useful for attenuating neuronal damage, suggesting a strategy for cerebral protection against global ischemia.