Hirano Seishiro, Kanno Sanae, Furuyama Akiko
Environmental Nanotoxicology Section, RCER, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
Toxicol Appl Pharmacol. 2008 Oct 15;232(2):244-51. doi: 10.1016/j.taap.2008.06.016. Epub 2008 Jul 3.
Carbon nanotubes (CNTs) are emerging nanotechnology materials which are likely to be mass-produced in the near future. However, prior to mass-production, certain health-related concerns should first be addressed. For example, when inhaled, the thin-fibrous shape and the biopersistent characteristics of CNTs may cause pulmonary diseases, in a manner similar to asbestos. In the present study, mouse macrophages (J774.1) were exposed to highly-purified multi-walled CNTs (MWCNTs, 67 nm) or to UICC crocidolite in order to evaluate the toxicity of these nano-size fibers. The cytotoxicity of MWCNTs was found to be higher than that of crocidolite. The toxic effect of MWCNTs was not affected by N-acetylcysteine, an antioxidant, or buthionine sulfoximine, a glutathione synthesis inhibitor. cDNA microarray analyses suggested that the cytotoxicity of MWCNTs could not be explained satisfactorily by either an increase or decrease of gene expression, although mRNA levels of some cytokines were slightly increased by MWCNTs. Moreover, MWCNTs did not significantly activate either MAP kinases such as ERK, JNK and p38, nor common apoptosis pathways such as caspase 3 and PARP. Electron microscopic studies indicated that MWCNTs associate with the plasma membrane of macrophages and disrupt the integrity of the membrane. Several proteins were found to adsorb onto MWCNTs when MWCNT-exposed macrophages were gently lysed. One of these proteins was macrophage receptor with collagenous structure (MARCO). MARCO-transfected CHO-K1 cells associated with MWCNTs more rapidly than mock-transfected cells. These results indicate that MWCNTs probably trigger cytotoxic effects in phagocytotic cells by reacting with MARCO on the plasma membrane and rupturing the plasma membrane.
碳纳米管（CNTs）是新兴的纳米技术材料，在不久的将来可能会大规模生产。然而，在大规模生产之前，某些与健康相关的问题应首先得到解决。例如，当被吸入时，碳纳米管的细纤维形状和生物持久性特征可能会以类似于石棉的方式导致肺部疾病。在本研究中，将小鼠巨噬细胞（J774.1）暴露于高度纯化的多壁碳纳米管（MWCNTs，67纳米）或国际癌症研究机构（UICC）标准的青石棉中，以评估这些纳米尺寸纤维的毒性。发现多壁碳纳米管的细胞毒性高于青石棉。多壁碳纳米管的毒性作用不受抗氧化剂N - 乙酰半胱氨酸或谷胱甘肽合成抑制剂丁硫氨酸亚砜胺的影响。cDNA微阵列分析表明，尽管多壁碳纳米管使一些细胞因子的mRNA水平略有升高，但多壁碳纳米管的细胞毒性无法通过基因表达的增加或减少得到满意的解释。此外，多壁碳纳米管既没有显著激活丝裂原活化蛋白激酶（MAP激酶）如细胞外信号调节激酶（ERK）、应激活化蛋白激酶（JNK）和p38，也没有激活常见的凋亡途径如半胱天冬酶3（caspase 3）和聚（ADP - 核糖）聚合酶（PARP）。电子显微镜研究表明，多壁碳纳米管与巨噬细胞的质膜结合并破坏膜的完整性。当轻轻裂解暴露于多壁碳纳米管的巨噬细胞时，发现几种蛋白质吸附在多壁碳纳米管上。其中一种蛋白质是具有胶原结构的巨噬细胞受体（MARCO）。与 mock - 转染细胞相比，转染了MARCO的中国仓鼠卵巢细胞（CHO - K1）与多壁碳纳米管的结合更快。这些结果表明，多壁碳纳米管可能通过与质膜上的MARCO反应并破坏质膜，从而在吞噬细胞中引发细胞毒性作用。
