Bhuiyan M I H, Kim J-C, Hwang S-N, Lee M-Y, Kim S Y
Department of Pharmacology, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul 137-701, South Korea; Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul 137-701, South Korea.
Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul 137-701, South Korea; Department of Anatomy, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul 137-701, South Korea.
Neuroscience. 2015 Apr 2;290:90-102. doi: 10.1016/j.neuroscience.2015.01.025. Epub 2015 Jan 28.
The functions of vascular endothelial growth factor C (VEGF-C) and the VEGF receptor 3 (VEGFR-3) in the nervous system are not well known. In this study, we examined the role of VEGF-C and VEGFR-3 in ischemic preconditioning (IPC)-induced tolerance in the mouse hippocampus. Adult male C57BL/6 mice were subjected to either severe ischemia (SI) induced by 40 min of bilateral common carotid artery occlusion (BCCAO) with or without IPC (5-min BCCAO) or IPC only. Cerebral blood flow was measured during ischemic periods using laser Doppler flowmetry. Neuronal damage was assessed histologically, and VEGF-C and VEGFR-3 expression levels were assessed through immunostaining. Fluoro-Jade B-labeled cells were abundant in the CA1 area 7 days after SI without IPC (sham+SI group), whereas cells were rarely labeled in mice subjected to IPC followed by SI (IPC+SI group). Similarly, the number of neuronal nuclei (NeuN)-positive cells in the CA1 area was significantly lower in the sham+SI group than in the IPC+SI group. Interestingly, we found that sublethal IPC treatment induced prominent VEGF-C expression in the CA1 pyramidal neurons and VEGFR-3 expression in the stratum radiatum and stratum lacunosum moleculare after 3 days of reperfusion that were sustained for 7 days. Moreover, VEGF-C immunoreactivity was also markedly increased, whereas VEGFR-3 expression was sustained in tolerance-acquired CA1 neurons after SI. Application of a VEGFR-3 inhibitor, SAR131675, abolished the IPC-induced neuroprotection in a dose-dependent manner in the mouse hippocampus. These results suggest that VEGF-C/VEGFR-3 signaling is associated with IPC-induced hippocampal tolerance to lethal ischemia.
血管内皮生长因子C（VEGF-C）和血管内皮生长因子受体3（VEGFR-3）在神经系统中的功能尚不清楚。在本研究中，我们检测了VEGF-C和VEGFR-3在小鼠海马缺血预处理（IPC）诱导的耐受性中的作用。成年雄性C57BL/6小鼠接受40分钟双侧颈总动脉闭塞（BCCAO）诱导的严重缺血（SI），有无IPC（5分钟BCCAO）或仅接受IPC。在缺血期间使用激光多普勒血流仪测量脑血流量。通过组织学评估神经元损伤，并通过免疫染色评估VEGF-C和VEGFR-3的表达水平。在无IPC的SI后7天，氟玉红B标记的细胞在CA1区大量存在（假手术+SI组），而在接受IPC后再进行SI的小鼠中（IPC+SI组）细胞很少被标记。同样，假手术+SI组CA1区神经元核（NeuN）阳性细胞数量明显低于IPC+SI组。有趣的是，我们发现亚致死性IPC处理在再灌注3天后诱导CA1锥体神经元中显著的VEGF-C表达以及辐射层和分子层隙状层中的VEGFR-3表达，并持续7天。此外，VEGF-C免疫反应性也显著增加，而VEGFR-3表达在SI后获得耐受性的CA1神经元中持续存在。应用VEGFR-3抑制剂SAR131675以剂量依赖性方式消除了小鼠海马中IPC诱导的神经保护作用。这些结果表明，VEGF-C/VEGFR-3信号通路与IPC诱导的海马对致死性缺血的耐受性有关。
