Synergistic Oxidative Stress of Surface Silanol and Hydroxyl Radical of Crystal and Amorphous Silica in A549 Cells
Synergistic Oxidative Stress of Surface Silanol and Hydroxyl Radical of Crystal and Amorphous Silica in A549 Cells
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A549细胞中晶体和无定形二氧化硅表面硅烷醇和羟基自由基的协同氧化应激
DOI：
10.1166/jnn.2017.14432
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发表时间：
2017
影响因子：
--
通讯作者：
Sun Dongping
中科院分区：
文献类型：
--
作者：
Huo Tingting;Dong Faqin;Yu Siwang;Tan Daoyong;Wang Pingping;Zhang Qingbi;Deng Jianjun;Sun Shiyong;Sun Dongping
研究了石英和纳米sio2两种二氧化硅样品的表面硅醇基团和诱导羟基自由基（·OH）。采用傅里叶变换红外光谱（FTIR）和电位滴定法对石英和纳米sio2的表面硅醇基团和表面位密度进行定性和定量测定。利用电子顺磁共振（ESR）光谱和荧光光谱测量了二氧化硅颗粒产生的·OH。采用共聚焦荧光显微镜和流式细胞术检测细胞内活性氧（ROS）。此外，通过超氧化物歧化酶（SOD）、谷胱甘肽（GSH）和细胞活力检测来评估氧化应激对A549细胞的影响。结果表明，在FTIR光谱中，只有非晶纳米sio2在953 cm−1处表现出Si-OH的弯曲。石英和纳米sio2的表面Si-OH位密度分别为0.31和1.14个/nm2。硅醇和Si-O·悬空键在表面催化H2O2均裂生成·OH，这在晶体石英颗粒中表现得尤为明显。·OH含量较高的石英对A549细胞的毒性较弱，但在A549细胞中观察到细胞内ROS急剧增加、GSH耗竭和细胞死亡率增高。高浓度的表面硅醇对A549细胞的毒性作用比·OH对纳米sio2的毒性作用更大。对二氧化硅颗粒无特异性，表面硅醇和表面形成的·OH均影响A549细胞的活力。此外，表面硅醇和二氧化硅颗粒生成的·OH对A549细胞的氧化应激具有协同作用。
The surface silanol groups and the induced hydroxyl radical (·OH) by two silica samples (Quartz and Nano-SiO2) were studied. The Fourier transform infrared spectroscopy (FTIR) and potentiometric titration were adopted to qualitatively and quantitatively determine the surface silanol groups and the surface site density of Quartz and Nano-SiO2. Electron paramagnetic resonance (ESR) spectroscopy and fluorescence spectra were used to measure the ·OH generated by the silica particles. The confocal fluorescence microscopy and flow cytometry were adopted to evaluate the intracellular reactive oxygen species (ROS). Additionally, superoxide dismutase (SOD), glutathione (GSH), and cell viability were tested for the assessment of oxidative stress in A549 cells induced by the surface silanol and ·OH of silica particles. The result showed that only the amorphous Nano-SiO2 exhibited the bending of Si–OH at 953 cm−1 in the FTIR spectra. The surface Si–OH site density of Quartz and Nano-SiO2 were 0.31 and 1.14 sites/nm2. The ·OH could form from the surface-catalyzed homolytic cleavage of H2O2 by silanol and the Si–O· dangling bonds, of which was remarkable for the crystal quartz particle. The Quartz with more ·OH production was less toxic to the A549 cells, while the dramatic increase of the intracellular ROS, depletion of GSH, and high cell mortality were observed in the A549 cells after the exposure to Nano-SiO2. The high concentration of surface silanol contributions to the toxic effects in A549 cells more than the ·OH for Nano-SiO2. Nonspecific for silica particles, both the surface silanol and ·OH formed on the surface effects the viability of A549 cells. Moreover, the surface silanol and the generated ·OH of silica particles exerted synergistic effect on the oxidative stress in A549 cells.