Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA.
J Toxicol Environ Health A. 2012;75(1):25-35. doi: 10.1080/15287394.2011.589105.
The aim of this study was to determine whether multiwalled carbon nanotubes (MWNCT) are taken up by and are toxic to human intestinal enterocytes using the Caco-2 cell model. Caco-2 cells were exposed to 50 μg/ml MWCNT (oxidized or pristine) for 24 h, and experiments were repeated in the presence of 2.5 mg/L natural organic matter. Cells displayed many of the properties that characterize enterocytes, such as apical microvilli, basolateral basement membrane, and glycogen. The cell monolayers also displayed tight junctions and electrical resistance. Exposure to pristine and oxidized MWCNT, with or without natural organic matter, did not markedly affect viability, which was assessed by measuring activity of released lactate dehydrogenase (LDH) and staining with propidium iodide. Ultrastructural analysis revealed some damage to microvilli colocalized with the MWCNT; however, neither type of MWCNT was taken up by Caco-2 cells. In contrast, pristine and oxidized MWCNT were taken up by the macrophage RAW 264.7 line. Our study suggests that intestinal enterocytes cells do not take up MWCNT.
本研究旨在使用 Caco-2 细胞模型确定多壁碳纳米管 (MWCNT) 是否被人肠上皮细胞摄取并具有毒性。Caco-2 细胞暴露于 50μg/ml MWCNT（氧化或原始）24 小时，并在 2.5mg/L 天然有机物存在下重复实验。细胞表现出许多特征性肠上皮细胞的特性，如顶微绒毛、基底膜和糖原。细胞单层还显示出紧密连接和电阻。暴露于原始和氧化 MWCNT，无论是否存在天然有机物，均未明显影响活力，通过测量释放的乳酸脱氢酶 (LDH) 的活性和碘化丙啶染色来评估活力。超微结构分析显示微绒毛的一些损伤与 MWCNT 共定位；然而，Caco-2 细胞均未摄取任何类型的 MWCNT。相比之下，原始和氧化 MWCNT 被巨噬细胞 RAW 264.7 系摄取。我们的研究表明，肠上皮细胞不摄取 MWCNT。
