College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, 310053, China.
Neurochem Res. 2021 Jun;46(6):1423-1434. doi: 10.1007/s11064-021-03281-6. Epub 2021 Mar 6.
A growing number of studies have shown that air fine particulate matter (PM) pollution is closely associated with neuroinflammation in humans. Militarine, a glucosyloxybenzyl 2-isobutylmalate compound isolated from Bletilla striata, has been found to exert significant neuroprotective effects. However, the anti-inflammatory, antioxidant and antiapoptotic effects of militarine on PM-stimulated BV-2 microglial cells have not been reported. This study aimed to investigate the protective effects of militarine against PM-induced cytotoxicity and its mechanism in BV-2 microglial cells. Our results revealed that pretreatment with 0.31-1.25 μg/mL militarine reversed the morphological changes caused by PM and decreased proinflammatory cytokine generation and gene expression in PM-treated BV-2 cells. In particular, tumor necrosis factor-α and interleukin-6 expression was inhibited in a dose-dependent manner. Notably, militarine markedly inhibited the upregulation of Toll-like receptor 4, Toll-like receptor 2, and cyclo-oxygenase-2 expression at both the mRNA and protein levels and reduced NF-κB pathway-associated protein expression. Immunofluorescence analysis showed that militarine suppressed NF-κB activity through inhibiting p65 nuclear translocation. Our data suggested that militarine alleviated neuroinflammation in BV-2 microglial cells, possibly by inhibiting the expression of neuroinflammatory cytokines through the TLR/NF-κB signaling pathway. Additionally, militarine significantly reduced PM-mediated reactive oxygen species (ROS) generation and cell apoptosis and restored the mitochondrial membrane potential (MMP; ΔΨm). Collectively, these findings demonstrate that militarine played a protective role against PM-induced damage in BV-2 cells by exerting anti-inflammatory, antioxidant, and antiapoptotic effects.
越来越多的研究表明，空气细颗粒物（PM）污染与人脑的神经炎症密切相关。从白及中分离得到的葡萄糖氧基苄基 2-异丁基马来酸酯化合物 Militarine 已被发现具有显著的神经保护作用。然而，Militarine 对 PM 刺激的 BV-2 小胶质细胞的抗炎、抗氧化和抗凋亡作用尚未见报道。本研究旨在探讨 Militarine 对 PM 诱导的 BV-2 小胶质细胞毒性的保护作用及其机制。我们的结果表明，0.31-1.25μg/mL 的 Militarine 预处理可逆转 PM 引起的形态变化，并降低 PM 处理的 BV-2 细胞中促炎细胞因子的产生和基因表达。特别是，肿瘤坏死因子-α和白细胞介素-6 的表达呈剂量依赖性抑制。值得注意的是，Militarine 可显著抑制 TLR4、TLR2 和环氧化酶-2 的表达，下调 NF-κB 通路相关蛋白的表达，这种抑制作用呈剂量依赖性。免疫荧光分析表明，Militarine 通过抑制 p65 核转位抑制 NF-κB 活性。我们的数据表明，Militarine 通过 TLR/NF-κB 信号通路抑制神经炎症细胞因子的表达，减轻了 BV-2 小胶质细胞中的神经炎症。此外，Militarine 还显著降低了 PM 介导的活性氧（ROS）生成和细胞凋亡，并恢复了线粒体膜电位（ΔΨm）。综上所述，这些发现表明，Militarine 通过发挥抗炎、抗氧化和抗凋亡作用，对 BV-2 细胞中 PM 诱导的损伤起到保护作用。
