Post-stroke treatment with argon attenuated brain injury, reduced brain inflammation and enhanced M2 microglia/macrophage polarization: a randomized controlled animal study
Post-stroke treatment with argon attenuated brain injury, reduced brain inflammation and enhanced M2 microglia/macrophage polarization: a randomized controlled animal study
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DOI：
10.1186/s13054-019-2493-7
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发表时间：
2019-06-03
期刊：
影响因子：
15.1
通讯作者：
Coburn, Mark
中科院分区：
文献类型：
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作者：
Liu, Jingjin;Nolte, Kay;Coburn, Mark
背景近年来，在一系列模型中，氩气被证明具有神经保护作用。然而，氩发挥其神经保护作用的机制仍不清楚。越来越多的证据表明，氩可能通过调节缺血性卒中后小胶质细胞/巨噬细胞的活化和极化来发挥神经保护作用。在本研究中，我们分析了延迟氩应用，直到7 d后再灌注的潜在的神经保护作用，并探讨了潜在的mechanism.MethodsTwenty-one雄性Wistar大鼠进行短暂的大脑中动脉闭塞或假手术随机为2 h使用的腔内线程模型。短暂性大脑中动脉闭塞诱导后3小时和再灌注后1小时，动物接受50%vol氩气/50%vol O-2或50%vol N-2/50%vol O-2 1小时。主要结局是再灌注后24 h至第7天的6分神经评分。还进行了组织学分析，包括梗死体积、缺血边界区的神经元存活（NeuN）、白色物质完整性（Luxol Fast Blue）、小胶质细胞/巨噬细胞活化（Iba 1）和第7天的极化（Iba 1/精氨酸酶1双染色）。使用nQuery Advisor + nTerim 4.0进行样本量计算。分别采用独立t检验、单因素方差分析和重复测量方差分析进行统计学分析（SPSS23.0）。结果再灌注后24 h至7 d 6点神经功能评分显示，tMCAO Ar组神经功能评分较tMCAO N-2组显著改善（p=0.026）。与tMCAO N-2组相比，tMCAO Ar组ROI中NeuN阳性细胞的相对数量显著增加（皮质p=0.010，皮质下p=0.011）。Iba 1染色显示，氩气显著抑制小胶质细胞/巨噬细胞活化（p=0.0076）并促进M2小胶质细胞/巨噬细胞极化，如Iba 1/Arginase 1双染色所示（p=0.000095）结论脑卒中后3 h和再灌注后1h给予氩气可明显减轻脑梗死后1周内的神经功能缺损，并保护缺血区神经元。脑卒中后7 d边界区。此外，氩气减少了过度的小胶质细胞/巨噬细胞活化，并促进了小胶质细胞/巨噬细胞极化向抗炎M2表型的转变。因此，进一步阐明其保护机制，为转基因应用提供理论依据，具有重要的研究价值。
BackgroundIn recent years, argon has been shown to exert neuroprotective effects in an array of models. However, the mechanisms by which argon exerts its neuroprotective characteristics remain unclear. Accumulating evidence imply that argon may exert neuroprotective effects via modulating the activation and polarization of microglia/macrophages after ischemic stroke. In the present study, we analyzed the underlying neuroprotective effects of delayed argon application until 7days after reperfusion and explored the potential mechanisms.MethodsTwenty-one male Wistar rats underwent transient middle cerebral artery occlusion or sham surgery randomly for 2h using the endoluminal thread model. Three hours after transient middle cerebral artery occlusion induction and 1h after reperfusion, animals received either 50% vol Argon/50% vol O-2 or 50% vol N-2/50% vol O-2 for 1h. The primary outcome was the 6-point neuroscore from 24h to d7 after reperfusion. Histological analyses including infarct volume, survival of neurons (NeuN) at the ischemic boundary zone, white matter integrity (Luxol Fast Blue), microglia/macrophage activation (Iba1), and polarization (Iba1/Arginase1 double staining) on d7 were conducted as well. Sample size calculation was performed using nQuery Advisor + nTerim 4.0. Independent t test, one-way ANOVA and repeated measures ANOVA were performed, respectively, for statistical analysis (SPSS 23.0).ResultsThe 6-point neuroscore from 24h to d7 after reperfusion showed that tMCAO Ar group displayed significantly improved neurological performance compared to tMCAO N-2 group (p=0.026). The relative numbers of NeuN-positive cells in the ROIs of tMCAO Ar group significantly increased compared to tMCAO N-2 group (p=0.010 for cortex and p=0.011 for subcortex). Argon significantly suppressed the microglia/macrophage activation as revealed by Iba1 staining (p=0.0076) and promoted the M2 microglia/macrophage polarization as revealed by Iba1/Arginase 1 double staining (p=0.000095).ConclusionsArgon administration with a 3h delay after stroke onset and 1h after reperfusion significantly alleviated neurological deficit within the first week and preserved the neurons at the ischemic boundary zone 7days after stroke. Moreover, argon reduced the excessive microglia/macrophage activation and promoted the switch of microglia/macrophage polarization towards the anti-inflammatory M2 phenotype. Studies making efforts to further elucidate the protective mechanisms and to benefit the translational application are of great value.