Department of Neurosurgery, First Bethune Hospital of Jilin University, Changchun, China.
PLoS One. 2013;8(2):e57869. doi: 10.1371/journal.pone.0057869. Epub 2013 Feb 28.
Complications due to brain edema and breakdown of blood brain barrier are an important factor affecting the treatment effects of patients with severe carotid stenosis. In this study, we investigated the protective effects of ischemic postconditioning on brain edema and disruption of blood brain barrier via establishing rat model of hypoperfusion due to severe carotid stenosis.
Wistar rat model of hypoperfusion due to severe carotid stenosis was established by binding a stainless microtube to both carotid arteries. Ischemic postconditioning procedure consisted of three cycles of 30 seconds ischemia and 30 seconds reperfusion. Brain edema was evaluated by measuring cerebral water content, and blood brain barrier permeability was assayed by examining cerebral concentration of Evans' Blue (EB) and fluorescein sodium (NaF). ELISA was used to analyze the expression of MMP-9, claudin-5 and occludin. The activity and location of MMP-9 was analyzed by gelatin zymography and in situ zymography, respectively. The distribution of tight junction proteins claudin-5 and occludin was observed by immunohistochemistry.
The increased brain water content and cerebral concentration of EB and NaF were suppressed by administration of ischemic postconditioning prior to relief of carotid stenosis. Zymographic studies showed that MMP-9 was mainly located in the cortex and its activity was significantly improved by relief of carotid stenosis and, but the elevated MMP-9 activity was inhibited markedly by ischemic postconditioning. Immunohistochemistry revealed that ischemic postconditioning improved the discontinuous distribution of claudin-5 and occludin. ELISA detected that the expression of up-regulated MMP-9 and down-regulated claudin-5 and occludin caused by carotid relief were all attenuated by ischemic postconditioning.
Ischemic postconditioning is an effective method to prevent brain edema and improve BBB permeability and could be used during relief of severe carotid stenosis.
脑水肿和血脑屏障破裂等并发症是影响重度颈动脉狭窄患者治疗效果的重要因素。本研究通过建立重度颈动脉狭窄所致低灌注大鼠模型，探讨缺血后处理对脑水肿和血脑屏障破坏的保护作用。
通过在双侧颈动脉上绑定不锈钢微管来建立重度颈动脉狭窄所致低灌注大鼠模型。缺血后处理程序包括三个 30 秒缺血和 30 秒再灌注循环。通过测量脑水含量评估脑水肿，通过检测伊文思蓝（EB）和荧光素钠（NaF）在脑内的浓度来评估血脑屏障通透性。ELISA 用于分析 MMP-9、claudin-5 和 occludin 的表达。通过明胶酶谱和原位酶谱分析 MMP-9 的活性和位置。通过免疫组织化学观察紧密连接蛋白 claudin-5 和 occludin 的分布。
缺血后处理可抑制颈动脉狭窄缓解后脑水含量、脑 EB 和 NaF 浓度的增加。酶谱研究表明，MMP-9 主要位于皮质，其活性在颈动脉狭窄缓解时显著升高，但缺血后处理可显著抑制升高的 MMP-9 活性。免疫组织化学显示，缺血后处理改善了 claudin-5 和 occludin 的不连续分布。ELISA 检测到，颈动脉缓解引起的 MMP-9 表达上调和 claudin-5、occludin 表达下调，均被缺血后处理所减弱。
缺血后处理是预防脑水肿和改善血脑屏障通透性的有效方法，可在重度颈动脉狭窄缓解期间使用。
