Effects of Erythropoietin on Blood-Brain Barrier Tight Junctions in Ischemia-Reperfusion Rats
Effects of Erythropoietin on Blood-Brain Barrier Tight Junctions in Ischemia-Reperfusion Rats
复制标题
促红细胞生成素对缺血再灌注大鼠血脑屏障紧密连接的影响
DOI：
10.1007/s12031-012-9883-5
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发表时间：
2013-02-01
影响因子：
3.1
通讯作者：
Xue, Yi-xue
中科院分区：
文献类型：
--
作者：
Liu, Kun;Sun, Tao;Xue, Yi-xue
重组人促红细胞生成素（rhEPO）可通过改善血脑屏障（BBB）通透性，保护脑缺血再灌注（I/R）后神经元免受损伤。但rhEPO对血脑屏障保护作用的机制尚不清楚。本研究旨在探讨rhEPO对脑缺血再灌注大鼠血脑屏障完整性及紧密连接相关蛋白紧密连接蛋白ZO-1、occludin和claudin-5表达的影响。这些大鼠经历2小时的缺血，然后再灌注长达3和72小时。将动物随机分为假手术组、缺血再灌注3 h组和缺血再灌注72 h组（缺血前腹腔注射生理盐水2 ml）、rhEPO +缺血再灌注3 h组和rhEPO +缺血再灌注72 h组（缺血前腹腔注射rhEPO 5, 000 U/kg/2 ml）。通过伊文思蓝外渗检测，证实rhEPO可减少I/R损伤所致的血脑屏障渗漏。2，3，5-三苯基四氮唑氯化物染色结果显示rhEPO可减少脑I/R后梗死体积。透射电镜观察到rhEPO可部分恢复TJ的完整性。逆转录-聚合酶链反应和Western blot检测结果显示，ZO-1、occludin和claudin-5的mRNA和蛋白表达水平均显著高于I/R组（P < 0. 05）。免疫组织化学染色观察到rhEPO处理诱导ZO-1、occludin和claudin-5在脑微血管中的重新分布。与I/R组相比，rhEPO治疗后脑微血管中肿瘤坏死因子-α（TNF-α）mRNA水平显著降低，同时伴有TNF-α蛋白水平降低和核因子-（DB）-B-0（NF-（DB）-B-0）p65活化。上述结果提示，rhEPO对脑I/R损伤后血脑屏障的保护机制与上调TJ相关蛋白有关。rhEPO诱导的TNF-α水平下调和NF-（DB）-B-0活化可能参与了这一过程。
Administration of recombinant human erythropoietin (rhEPO) protects neurons from injury after brain ischemia-reperfusion (I/R), which is in part mediated by ameliorating the blood-brain barrier (BBB) leakage. But the mechanism of rhEPO's protective effects on BBB remains unclear. This study aims to investigate the effects of rhEPO on BBB integrity and the expressions of tight junctions (TJs) associated proteins of zonula occluden-1 (ZO-1), occludin, and claudin-5 in cerebral I/R rats. These rats underwent 2 h of ischemia and then were reperfused for up to 3 and 72 h. Animals were randomly divided into five groups: sham-operated group, I/R 3 h and I/R 72 h group (2 ml saline was injected intraperitoneally just before the onset of ischemia), rhEPO + I/R 3 h, and rhEPO + I/R 72 h group (5,000 U/kg rhEPO diluted in 2 ml saline solution was injected intraperitoneally just before the onset of ischemia). We verified that rhEPO could decrease the BBB leakage induced by I/R injury detected by Evans blue extravasation. 2, 3, 5-Triphenyltetrazolium chloride staining results showed that rhEPO decreased infarct volume after cerebral I/R. TJ integrity was partly restored by rhEPO observed by transmission electron microscopy. The mRNA and protein expression levels of ZO-1, occludin, and claudin-5 were significantly increased compared with I/R groups at the same reperfusion time point by reverse transcriptase-polymerase chain reaction and Western blot assays. The treatment of rhEPO induced the redistribution of ZO-1, occludin, and claudin-5 in cerebral microvessels observed by immunohistochemical staining. Compared with I/R groups, the mRNA level of tumor necrosis factor-alpha (TNF-alpha) in cerebral microvessels decreased markedly after rhEPO treatment, accompanied with reduced TNF-alpha protein level and nuclear factor-(DB)-B-0 (NF-(DB)-B-0) p65 activation detected by enzyme-linked immunosorbent assay. These results suggested that the protective mechanism of rhEPO on BBB after cerebral I/R injury was associated with the upregulation of TJ-associated proteins. The downregulated TNF-alpha levels and NF-(DB)-B-0 activation induced by rhEPO might be involved in this process.