Pharmacological and genetic inhibition of NADPH oxidase does not reduce brain damage in different models of perinatal brain injury in newborn mice
Pharmacological and genetic inhibition of NADPH oxidase does not reduce brain damage in different models of perinatal brain injury in newborn mice
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DOI：
10.1016/j.nbd.2008.04.003
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发表时间：
2008-07-01
影响因子：
6.1
通讯作者：
Savman, Karin
中科院分区：
文献类型：
--
作者：
Doverhag, Christina;Keller, Matthias;Savman, Karin
背景：炎症和活性氧（ROS）在围产期脑损伤的发生发展中起重要作用。ROS生成酶NADPH氧化酶（Nox 2）存在于炎性细胞中，并在成年动物模型中导致脑损伤。假设：NADPH氧化酶有助于ROS的形成和未成熟脑损伤的发展，抑制NADPH氧化酶可减轻围产期脑损伤。我们使用了长期缺氧缺血（HI）（139只小鼠）以及鹅膏蕈氨酸诱导的兴奋性毒性损伤（P5小鼠）的动物模型，模拟早产儿脑室周围白质软化的特征。在体外小胶质细胞培养物被用来研究NADPH氧化酶依赖的ROS的形成。在体内，我们分别测定了1）HI对NADPH氧化酶基因表达的影响，2）遗传（gp 91-phox/Nox 2敲除）和3）药理学NADPH氧化酶抑制对HI诱导的损伤和NMDA受体介导的兴奋性毒性损伤的影响。结果：缺氧缺血可增加在体全脑组织NADPH氧化酶亚基mRNA的表达。体外鹅膏蕈氨酸增加小胶质细胞中NADPH氧化酶依赖的活性氧的形成。在体内抑制NADPH氧化酶并没有减少任何动物模型中的脑损伤程度。与此相反，NADPH氧化酶的抑制则增加了损伤程度，基因抑制与半乳糖凝集素-3和IL-1 β水平的增加有关。结论：缺氧缺血后NADPH氧化酶表达上调，活化的小胶质细胞可能是Nox 2源性ROS的来源。与成人脑中的发现相反，NADPH氧化酶对围产期脑损伤的发病机制没有显着贡献。在成年动物中获得的结果不能转移到新生动物，并且NADPH氧化酶的抑制不应用于试图减轻损伤。(C)2008年爱思唯尔公司All rights reserved.
Background: Inflammation and reactive oxygen species (ROS) are important in the development of perinatal brain injury. The ROS-generating enzyme NADPH oxidase (Nox2) is present in inflammatory cells and contributes to brain injury in adult animal models.Hypothesis: NADPH oxidase contributes to ROS formation and development of injury in the immature brain and inhibition of NADPH oxidase attenuates perinatal brain injury.Methods: We used animal models of term hypoxia-ischemia (HI) (139 mice) as well as ibotenate-induced excitotoxic injury (P5 mice) mimicking features of periventricular leukomalacia in preterm infants. In vitro microglia cell cultures were used to investigate NADPH oxidase-dependent ROS formation. In vivo we determined the impact 1) of HI on NADPH oxidase gene expression 2) of genetic (gp91-phox/Nox2 knock-out) and 3) of pharmacological NADPH oxidase inhibition on HI-induced injury and NMDA receptor-mediated excitotoxic injury, respectively. Endpoints were ROS formation, oxidative stress, apoptosis, inflammation and extent of injury.Results: Hypoxia-ischemia increased NADPH oxidase subunits mRNA expression in total brain tissue in vivo. In vitro ibotenate increased NADPH oxidase-dependent formation of reactive oxygen species in microglia. In vivo the inhibition of NADPH oxidase did not reduce the extent of brain injury in any of the animal models. In contrast, the injury was increased by inhibition of NADPH oxidase and genetic inhibition was associated with an increased level of galectin-3 and IL-1 beta.Conclusion: NADPH oxidase is upregulated after hypoxia-ischemia and activated microglia cells are a possible source of Nox2-derived ROS. In contrast to findings in adult brain, NADPH oxidase does not significantly contribute to the pathogenesis of perinatal brain injury. Results obtained in adult animals cannot be transferred to newborns and inhibition of NADPH oxidase should not be used in attempts to attenuate injury. (C) 2008 Elsevier Inc. All rights reserved.