Wang Li-Feng, Li Xiang, Gao Ya-Bing, Wang Shui-Ming, Zhao Li, Dong Ji, Yao Bin-Wei, Xu Xin-Ping, Chang Gong-Min, Zhou Hong-Mei, Hu Xiang-Jun, Peng Rui-Yun
Laboratory of Experimental Pathology, Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing, 100850, China.
Mol Neurobiol. 2015 Aug;52(1):478-91. doi: 10.1007/s12035-014-8848-9. Epub 2014 Sep 9.
Microwaves have been suggested to induce neuronal injury and increase permeability of the blood-brain barrier (BBB), but the mechanism remains unknown. The role of the vascular endothelial growth factor (VEGF)/Flk-1-Raf/MAPK kinase (MEK)/extracellular-regulated protein kinase (ERK) pathway in structural and functional injury of the blood-brain barrier (BBB) following microwave exposure was examined. An in vitro BBB model composed of the ECV304 cell line and primary rat cerebral astrocytes was exposed to microwave radiation (50 mW/cm(2), 5 min). The structure was observed by scanning electron microscopy (SEM) and the permeability was assessed by measuring transendothelial electrical resistance (TEER) and horseradish peroxidase (HRP) transmission. Activity and expression of VEGF/Flk-1-ERK pathway components and occludin also were examined. Our results showed that microwave radiation caused intercellular tight junctions to broaden and fracture with decreased TEER values and increased HRP permeability. After microwave exposure, activation of the VEGF/Flk-1-ERK pathway and Tyr phosphorylation of occludin were observed, along with down-regulated expression and interaction of occludin with zonula occludens-1 (ZO-1). After Flk-1 (SU5416) and MEK1/2 (U0126) inhibitors were used, the structure and function of the BBB were recovered. The increase in expression of ERK signal transduction molecules was muted, while the expression and the activity of occludin were accelerated, as well as the interactions of occludin with p-ERK and ZO-1 following microwave radiation. Thus, microwave radiation may induce BBB damage by activating the VEGF/Flk-1-ERK pathway, enhancing Tyr phosphorylation of occludin, while partially inhibiting expression and interaction of occludin with ZO-1.
已有研究表明，微波可导致神经元损伤并增加血脑屏障（BBB）的通透性，但其机制尚不清楚。本研究检测了血管内皮生长因子（VEGF）/Flk-1-raf/丝裂原活化蛋白激酶激酶（MEK）/细胞外调节蛋白激酶（ERK）通路在微波暴露后血脑屏障（BBB）结构和功能损伤中的作用。将由ECV304细胞系和原代大鼠脑星形胶质细胞组成的体外血脑屏障模型暴露于微波辐射（50 mW/cm²，5分钟）。通过扫描电子显微镜（SEM）观察结构，并通过测量跨内皮电阻（TEER）和辣根过氧化物酶（HRP）透过率评估通透性。还检测了VEGF/Flk-1-ERK通路成分和闭合蛋白的活性及表达。我们的结果表明，微波辐射导致细胞间紧密连接变宽和断裂，TEER值降低，HRP通透性增加。微波暴露后，观察到VEGF/Flk-1-ERK通路激活和闭合蛋白的酪氨酸磷酸化，同时闭合蛋白与紧密连接蛋白-1（ZO-1）的表达和相互作用下调。使用Flk-1（SU5416）和MEK1/2（U0126）抑制剂后，血脑屏障的结构和功能得以恢复。微波辐射后，ERK信号转导分子的表达增加受到抑制，而闭合蛋白的表达和活性加快，以及闭合蛋白与p-ERK和ZO-1的相互作用加快。因此，微波辐射可能通过激活VEGF/Flk-1-ERK通路、增强闭合蛋白的酪氨酸磷酸化，同时部分抑制闭合蛋白与ZO-1的表达和相互作用来诱导血脑屏障损伤。
