Department of Pathology at the Affiliated Hospital of Guizhou Medical University, Key Laboratory of Endemic and Ethnic Diseases (Guizhou Medical University) of the Ministry of Education, Guiyang, China.
Department of Medical Science and Technology, Guiyang Healthcare Vocational University, Guiyang, China.
CNS Neurosci Ther. 2023 Apr;29(4):1129-1141. doi: 10.1111/cns.14090. Epub 2023 Jan 17.
For investigating the mechanism of brain injury caused by chronic fluorosis, this study was designed to determine whether NRH:quinone oxidoreductase 2 (NQO2) can influence autophagic disruption and oxidative stress induced in the central nervous system exposed to a high level of fluoride.
Sprague-Dawley rats drank tap water containing different concentrations of fluoride for 3 or 6 months. SH-SY5Y cells were either transfected with NQO2 RNA interference or treated with NQO2 inhibitor or activator and at the same time exposed to fluoride. The enrichment of gene signaling pathways related to autophagy was evaluated by Gene Set Enrichment Analysis; expressions of NQO2 and autophagy-related protein 5 (ATG5), LC3-II and p62, and mammalian target of rapamycin (mTOR) were quantified by Western-blotting or fluorescent staining; and the levels of malondialdehyde (MDA) and superoxide dismutase (SOD) assayed biochemically and reactive oxygen species (ROS) detected by flow cytometry.
In the hippocampal CA3 region of rats exposed to high fluoride, the morphological characteristics of neurons were altered; the numbers of autophagosomes in the cytoplasm and the levels of NQO2 increased; the level of p-mTOR was decreased, and the levels of ATG5, LC3-II and p62 were elevated; and genes related to autophagy enriched. In vitro, in addition to similar changes in NQO2, p-mTOR, ATG5, LC3 II, and p62, exposure of SH-SY5Y cells to fluoride enhanced MDA and ROS contents and reduced SOD activity. Inhibition of NQO2 with RNAi or an inhibitor attenuated the disturbance of the autophagic flux and enhanced oxidative stress in these cells exposed to high fluoride.
Our findings indicate that NQO2 may be involved in regulating autophagy and oxidative stress and thereby exerts an impact on brain injury caused by chronic fluorosis.
为了研究慢性氟中毒引起的脑损伤机制，本研究旨在确定 NRH：醌氧化还原酶 2（NQO2）是否会影响中枢神经系统暴露于高水平氟化物后引发的自噬破坏和氧化应激。
Sprague-Dawley 大鼠饮用含有不同浓度氟化物的自来水 3 或 6 个月。用 NQO2 RNA 干扰转染 SH-SY5Y 细胞或用 NQO2 抑制剂或激活剂处理 SH-SY5Y 细胞，同时暴露于氟化物下。通过基因集富集分析评估与自噬相关的基因信号通路的富集情况；通过 Western-blotting 或荧光染色定量测定 NQO2 和自噬相关蛋白 5（ATG5）、LC3-II 和 p62 的表达；以及通过生化方法测定丙二醛（MDA）和超氧化物歧化酶（SOD）的水平，并通过流式细胞术检测活性氧（ROS）的水平。
在暴露于高氟化物的大鼠海马 CA3 区，神经元的形态特征发生改变；细胞质中的自噬体数量增加，NQO2 水平升高；p-mTOR 水平降低，ATG5、LC3-II 和 p62 水平升高；与自噬相关的基因富集。体外，除了 NQO2、p-mTOR、ATG5、LC3 II 和 p62 发生类似变化外，氟化物暴露还增强了 SH-SY5Y 细胞 MDA 和 ROS 的含量，降低了 SOD 的活性。用 RNAi 或抑制剂抑制 NQO2 减弱了这些细胞暴露于高氟化物后自噬流的紊乱并增强了氧化应激。
我们的研究结果表明，NQO2 可能参与调节自噬和氧化应激，从而对慢性氟中毒引起的脑损伤产生影响。
