National Institute for Occupational Safety and Health, Health Effects Laboratory Division, Morgantown, WV, USA.
Department of Mechanical & Aerospace Engineering, West Virginia University, Morgantown, WV, USA.
Inhal Toxicol. 2020 Jan;32(1):24-38. doi: 10.1080/08958378.2020.1723746. Epub 2020 Feb 7.
In this study, we compared and bioactivity of nitrogen-doped multi-walled carbon nanotubes (NDMWCNT) to MWCNT to test the hypothesis that nitrogen doping would alter bioactivity. High-resolution transmission electron microscopy (TEM) confirmed the multilayer structure of MWCNT with an average layer distance of 0.36 nm, which was not altered by nitrogen doping: the nanomaterials had similar widths and lengths. studies with THP-1 cells and alveolar macrophages from C57BL/6 mice demonstrated that NDMWCNT were less cytotoxic and stimulated less IL-1β release compared to MWCNT. For studies, male C57BL/6J mice received a single dose of dispersion medium (DM), 2.5, 10 or 40 µg/mouse of NDMWCNT, or 40 µg/mouse of MWCNT by oropharyngeal aspiration. Animals were euthanized between 1 and 7 days post-exposure for whole lung lavage (WLL) studies. NDMWCNT caused time- and dose-dependent pulmonary inflammation. However, it was less than that caused by MWCNT. Activation of the NLRP3 inflammasome was assessed in particle-exposed mice by determining cytokine production in WLL fluid at 1 day post-exposure. Compared to DM-exposed mice, IL-1β and IL-18 were significantly increased in MWCNT- and NDMWCNT-exposed mice, but the increase caused by NDMWCNT was less than MWCNT. At 56 days post-exposure, histopathology determined lung fibrosis in MWCNT-exposed mice was greater than NDMWCNT-exposed mice. These data indicate nitrogen doping of MWCNT decreases their bioactivity, as reflected with lower and toxicity inflammation and lung disease. The lower activation of the NLRP3 inflammasome may be responsible. NDMWCNT: nitrogen-doped multi-walled carbon nanotubes; MWCNT: multi-walled carbon nanotubes; TEM: transmission electron microscopy; HRTEM: high resolution transmission electron microscopy; IL-1ß: interleukin-1ß; DM: dispersion medium; WLL: whole lung lavage; IL-18: interleukin-18; GSD: geometric standard deviation; XPS: X-ray photoelectron spectroscopy; SEM: standard error of the mean; PMA: phorbol 12-myristate 13-acetate; LPS: lipopolysacharride; LDH: lactate dehydrogenase; AM: alveolar macrophage; PMN: polymorphonuclear leukocyte.
在这项研究中，我们比较了氮掺杂多壁碳纳米管（NDMWCNT）和 MWCNT 的生物活性，以验证氮掺杂会改变生物活性的假设。高分辨率透射电子显微镜（TEM）证实了 MWCNT 的多层结构，平均层间距为 0.36nm，氮掺杂并未改变这一点：纳米材料具有相似的宽度和长度。与 THP-1 细胞和 C57BL/6 小鼠的肺泡巨噬细胞的研究表明，与 MWCNT 相比，NDMWCNT 的细胞毒性更低，释放的 IL-1β 更少。对于体内研究，雄性 C57BL/6J 小鼠通过口咽吸入接受 2.5、10 或 40μg/小鼠的 NDMWCNT 或 40μg/小鼠的 MWCNT 的分散介质（DM）单次剂量。动物在暴露后 1 至 7 天内处死，进行全肺灌洗（WLL）研究。NDMWCNT 引起时间和剂量依赖性的肺部炎症。然而，其程度低于 MWCNT。通过在暴露后 1 天测定 WLL 液体中的细胞因子产生，评估 NLRP3 炎性体在颗粒暴露小鼠中的激活。与 DM 暴露的小鼠相比，MWCNT 和 NDMWCNT 暴露的小鼠的 IL-1β 和 IL-18 显著增加，但 NDMWCNT 引起的增加小于 MWCNT。在暴露后 56 天，MWCNT 暴露的小鼠的组织病理学确定的肺纤维化大于 NDMWCNT 暴露的小鼠。这些数据表明，MWCNT 的氮掺杂降低了其生物活性，这反映在较低的细胞毒性和炎症以及肺部疾病上。较低的 NLRP3 炎性体的激活可能是其原因。NDMWCNT：氮掺杂多壁碳纳米管；MWCNT：多壁碳纳米管；TEM：透射电子显微镜；HRTEM：高分辨率透射电子显微镜；IL-1β：白细胞介素-1β；DM：分散介质；WLL：全肺灌洗；IL-18：白细胞介素-18；GSD：几何标准偏差；XPS：X 射线光电子能谱；SEM：标准误差均值；PMA：佛波醇 12-肉豆蔻酸 13-乙酸酯；LPS：脂多糖；LDH：乳酸脱氢酶；AM：肺泡巨噬细胞；PMN：多形核白细胞。
