NETRIN-1 RESCUES NEURON LOSS BY ATTENUATING SECONDARY APOPTOSIS IN IPSILATERAL THALAMIC NUCLEUS FOLLOWING FOCAL CEREBRAL INFARCTION IN HYPERTENSIVE RATS
NETRIN-1 RESCUES NEURON LOSS BY ATTENUATING SECONDARY APOPTOSIS IN IPSILATERAL THALAMIC NUCLEUS FOLLOWING FOCAL CEREBRAL INFARCTION IN HYPERTENSIVE RATS
复制标题
Netrin-1 通过减弱高血压大鼠局灶性脑梗死后同侧丘脑核的继发性细胞凋亡来挽救神经元损失
DOI：
10.1016/j.neuroscience.2012.11.059
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发表时间：
2013-02-12
期刊：
影响因子：
3.3
通讯作者：
Yu, J.
中科院分区：
文献类型：
--
作者：
Liao, S-J.;Gong, Q.;Yu, J.
脑梗死后的神经功能缺损不仅与原发性损伤有关，而且与梗死相关的远端部位的继发性神经元凋亡有关。Netrin-1通过与其受体相互作用对轴突导向至关重要，在结直肠癌（DCC）和不协调基因5 H（UNC 5 H）中缺失。DCC和UNC 5 H也是当未被netrin-1结合时诱导细胞凋亡的依赖性受体。本研究旨在探讨netrin-1及其受体在高血压大鼠脑卒中后同侧丘脑腹后核（ventroposterior thalamic nucleus，VPN）损伤中的作用。肾血管性高血压Sprague-Dawley大鼠进行大脑中动脉闭塞（MCAO）。在MCAO后24 h给予netrin-1（600 ng/d，持续7天）或溶媒（IgG/Fc）连续脑室内输注。术后第8天和第14天通过姿势反射评价神经功能。然后，在同侧VPN中测定NeuN、胶质细胞酸性蛋白、netrin-1及其受体（DCC和UNC 5 H2）的免疫反应性，用末端脱氧核苷酸转移酶介导的地高辛-dUTP-生物素缺口末端标记（TUNEL）法检测细胞凋亡，并通过western blot分析定量caspase-3、netrin-1、DCC和UNC 5 H2的表达。MCAO后第8天和第14天的姿势反射受损，NeuN标记的神经元减少，TUNEL阳性细胞增加，以及在同侧VPN中裂解的caspase-3和UNC 5 H2蛋白水平上调，而DCC或netrin-1表达无显著变化。注射外源性netrin-1后，大鼠同侧VPN神经元数量增加，TUNEL阳性细胞数减少，caspase-3蛋白水平降低，而UNC 5 H2表达无明显变化，姿势反射障碍得到改善。综上所述，本研究表明，外源性netrin-1可以通过减轻局灶性脑梗死后同侧VPN中的继发性凋亡来挽救神经元损失，可能通过其受体UNC 5 H2，这表明内源性netrin-1的相对不足是卒中后VPN继发性损伤的潜在机制。(c)2012年IBRO。由爱思唯尔有限公司出版。保留所有权利。
Neurological deficit following cerebral infarction correlates with not only primary injury, but also secondary neuronal apoptosis in remote loci connected to the infarction. Netrin-1 is crucial for axonal guidance by interacting with its receptors, deleted in colorectal cancer (DCC) and uncoordinated gene 5H (UNC5H). DCC and UNC5H are also dependence receptors inducing cell apoptosis when unbound by netrin-1. The present study is to investigate the role of netrin-1 and its receptors in ipsilateral ventroposterior thalamic nucleus (VPN) injury secondary to stroke in hypertensive rats. Renovascular hypertensive Sprague-Dawley rats underwent middle cerebral artery occlusion (MCAO). Continuous intracerebroventricular infusion of netrin-1 (600 ng/d for 7 days) or vehicle (IgG/Fc) was given 24 h after MCAO. Neurological function was evaluated by postural reflex 8 and 14 days after MCAO. Then, immunoreactivity was determined in the ipsilateral VPN for NeuN, glial fibrillary acidic protein, netrin-1 and its receptors (DCC and UNC5H2), apoptosis was detected with Terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP-biotin nick-end labeling (TUNEL) assay, and the expressions of caspase-3, netrin-1, DCC, and UNC5H2 were quantified by western blot analysis. MCAO resulted in the impaired postural reflex after 8 and 14 days, with decreased NeuN marked neurons and increased TUNEL-positive cells, as well as an up-regulation in the levels of cleaved caspase-3 and UNC5H2 protein in the ipsilateral VPN, without significant change in DCC or netrin-1 expression. By exogenous netrin-1 infusion, the number of neurons was increased in the ipsilateral VPN, and both TUNEL-positive cell number and caspase-3 protein level were reduced, while UNC5H2 expression remained unaffected, simultaneously, the impairment of postural reflex was improved. Taken together, the present study indicates that exogenous netrin-1 could rescue neuron loss by attenuating secondary apoptosis in the ipsilateral VPN after focal cerebral infarction, possibly via its receptor UNC5H2, suggesting that relative insufficiency of endogenous netrin-1 be an underlying mechanism of secondary injury in the VPN post stroke. (c) 2012 IBRO. Published by Elsevier Ltd. All rights reserved.