King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451, Saudi Arabia.
Int J Environ Res Public Health. 2020 Nov 6;17(21):8221. doi: 10.3390/ijerph17218221.
Combined exposure of single-walled carbon nanotubes (SWCNTs) and trace metal lead (Pb) in ambient air is unavoidable. Most of the previous studies on the toxicity of SWCNTs and Pb have been conducted individually. There is a scarcity of information on the combined toxicity of SWCNTs and Pb in human cells. This work was designed to explore the combined effects of SWCNTs and Pb in human lung epithelial (A549) cells. SWCNTs were prepared through the plasma-enhanced vapor deposition technique. Prepared SWCNTs were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, and dynamic light scattering. We observed that SWCNTs up to a concentration of 100 µg/mL was safe, while Pb induced dose-dependent (5-100 µg/mL) cytotoxicity in A549 cells. Importantly, cytotoxicity, cell cycle arrest, mitochondrial membrane potential depletion, lipid peroxidation, and induction of caspase-3 and -9 enzymes following Pb exposure (50 µg/mL for 24 h) were efficiently attenuated by the co-exposure of SWCNTs (10 µg/mL for 24 h). Furthermore, generation of Pb-induced pro-oxidants (reactive oxygen species and hydrogen peroxide) and the reduction of antioxidants (antioxidant enzymes and glutathione) were also mitigated by the co-exposure of SWCNTs. Inductively coupled plasma-mass spectrometry results suggest that the adsorption of Pb on the surface of SWCNTs could attenuate the bioavailability and toxicity of Pb in A549 cells. Our data warrant further research on the combined effects of SWCNTs and Pb in animal models.
在环境空气中，单壁碳纳米管 (SWCNTs) 和痕量金属铅 (Pb) 的联合暴露是不可避免的。之前大多数关于 SWCNTs 和 Pb 毒性的研究都是单独进行的。关于 SWCNTs 和 Pb 在人类细胞中的联合毒性的信息很少。这项工作旨在探索 SWCNTs 和 Pb 在人肺上皮 (A549) 细胞中的联合效应。通过等离子体增强气相沉积技术制备 SWCNTs。通过 X 射线衍射、X 射线光电子能谱、扫描电子显微镜和动态光散射对制备的 SWCNTs 进行了表征。我们观察到，SWCNTs 的浓度高达 100 µg/mL 是安全的，而 Pb 诱导了 A549 细胞中剂量依赖性的细胞毒性（5-100 µg/mL）。重要的是，Pb 暴露（24 小时 50 µg/mL）后引起的细胞毒性、细胞周期停滞、线粒体膜电位耗竭、脂质过氧化以及 caspase-3 和 -9 酶的诱导，通过 SWCNTs 的共同暴露（24 小时 10 µg/mL）得到了有效缓解。此外，Pb 诱导的促氧化剂（活性氧和过氧化氢）的产生以及抗氧化剂（抗氧化酶和谷胱甘肽）的减少也通过 SWCNTs 的共同暴露得到缓解。电感耦合等离子体质谱结果表明，Pb 吸附在 SWCNTs 表面可以减轻 Pb 在 A549 细胞中的生物利用度和毒性。我们的数据证明了在动物模型中进一步研究 SWCNTs 和 Pb 的联合效应的必要性。
