Repetitive hyperbaric oxygen exposures enhance sensitivity to convulsion by upregulation of eNOS and nNOS
Repetitive hyperbaric oxygen exposures enhance sensitivity to convulsion by upregulation of eNOS and nNOS
复制标题
重复高压氧暴露通过上调 eNOS 和 nNOS 增强对惊厥的敏感性
DOI：
10.1016/j.brainres.2008.01.068
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发表时间：
2008-03-27
期刊：
影响因子：
2.9
通讯作者：
Tao, Hengyi
中科院分区：
文献类型：
--
作者：
Liu, Wenwu;Li, Jiasi;Tao, Hengyi
背景：重复高压氧（HBO）暴露作为预处理方法可产生缺血耐受性，但可能增加患者惊厥的风险。本研究的目的是探讨反复暴露于高压氧后对惊厥敏感性增加的机制以及一氧化氮（NO）及其合酶的作用。方法：将小鼠随机分为三组：高压氧组（HBO）、高压空气组（HBA）和常压空气组（NBA）。HBO组和HBA组小鼠分别暴露于高压氧或高压空气中，每次60 min，每天2次，连续3天（2.5个大气压[ATA]）。最后一次暴露24 h后，小鼠暴露于HBO （100% o - 2,6 ATA）。记录抽搐潜伏期。测定大鼠下丘脑和海马组织NO水平、nadph - diaphase水平及NOS异构体mRNA和蛋白表达。结果：六次HBO预暴露后，小鼠癫痫发作潜伏期明显缩短。HBO组大鼠下丘脑NO水平升高。下丘脑和海马内NADPH-d阳性细胞数量增加，eNOS和nNOS蛋白及mRNA水平升高。结论：反复高压氧暴露后，一氧化氮升高可增强惊厥敏感性，并可能导致后续氧暴露时癫痫发作。HBO作为预处理方法时，需要预防癫痫发作。(C) 2008 Elsevier B.V.版权所有
Background: Repetitive hyperbaric oxygen (HBO) exposures as preconditioning methods produce ischemic tolerance, but may increase the risk of convulsions in patients. The purpose of this study was to investigate the mechanisms in increased sensitivity to convulsions and the role of nitric oxide (NO) and its synthases after repetitive HBO exposures. Methods: Mice were randomly assigned into three groups: HBO group, hyperbaric air (HBA) group and normobaric air (NBA) group. Mice in HBO or HBA group were exposed to hyperbaric oxygen or hyperbaric air respectively for 60 min twice daily for 3 consecutive days (2.5 atmosphere absolute [ATA]). 24 h after the last exposure, mice were exposed to HBO (100% O-2, 6 ATA). The latency of convulsions was recorded. In addition, the levels of NO, NADPH-diaphorase, mRNA and protein expressions of NOS isofonns in hypothalamus and hippocampus were determined. Results: Latency to seizures was significantly shortened in mice after six HBO pre-exposures. The level of NO in hypothalamus in HBO group was increased. The number of NADPH-d positive cells and the levels of protein and mRNA of eNOS and nNOS in hypothalamus and hippocampus were increased. Conclusion: After repeated HBO exposures, elevated NO may enhance the sensitivity to convulsions and this may lead to seizures during the subsequent oxygen exposures. Prevention of seizures is needed when HBO is used as preconditioning method. (C) 2008 Elsevier B.V. All rights reserved.