Lam Chiu-Wing, James John T, McCluskey Richard, Hunter Robert L
Space and Life Sciences, NASA Johnson Space Center, Houston, Texas 77058, USA.
Toxicol Sci. 2004 Jan;77(1):126-34. doi: 10.1093/toxsci/kfg243. Epub 2003 Sep 26.
Nanomaterials are part of an industrial revolution to develop lightweight but strong materials for a variety of purposes. Single-wall carbon nanotubes are an important member of this class of materials. They structurally resemble rolled-up graphite sheets, usually with one end capped; individually they are about 1 nm in diameter and several microns long, but they often pack tightly together to form rods or ropes of microscopic sizes. Carbon nanotubes possess unique electrical, mechanical, and thermal properties and have many potential applications in the electronics, computer, and aerospace industries. Unprocessed nanotubes are very light and could become airborne and potentially reach the lungs. Because the toxicity of nanotubes in the lung is not known, their pulmonary toxicity was investigated. The three products studied were made by different methods and contained different types and amounts of residual catalytic metals. Mice were intratracheally instilled with 0, 0.1, or 0.5 mg of carbon nanotubes, a carbon black negative control, or a quartz positive control and euthanized 7 d or 90 d after the single treatment for histopathological study of the lungs. All nanotube products induced dose-dependent epithelioid granulomas and, in some cases, interstitial inflammation in the animals of the 7-d groups. These lesions persisted and were more pronounced in the 90-d groups; the lungs of some animals also revealed peribronchial inflammation and necrosis that had extended into the alveolar septa. The lungs of mice treated with carbon black were normal, whereas those treated with high-dose quartz revealed mild to moderate inflammation. These results show that, for the test conditions described here and on an equal-weight basis, if carbon nanotubes reach the lungs, they are much more toxic than carbon black and can be more toxic than quartz, which is considered a serious occupational health hazard in chronic inhalation exposures.
纳米材料是工业革命的一部分，旨在开发用于各种目的的轻质但坚固的材料。单壁碳纳米管是这类材料的重要成员。它们在结构上类似于卷起的石墨片，通常一端封闭；单个碳纳米管的直径约为1纳米，长度为几微米，但它们常常紧密堆积在一起形成微观尺寸的棒或绳。碳纳米管具有独特的电学、力学和热学性质，在电子、计算机和航空航天工业中有许多潜在应用。未加工的纳米管非常轻，可能会悬浮在空气中并有可能进入肺部。由于纳米管在肺部的毒性未知，因此对其肺部毒性进行了研究。所研究的三种产品采用不同方法制造，含有不同类型和数量的残留催化金属。给小鼠气管内注入0、0.1或0.5毫克碳纳米管、炭黑阴性对照或石英阳性对照，单次处理后7天或90天实施安乐死，以便对肺部进行组织病理学研究。所有纳米管产品在7天组的动物中均诱导出剂量依赖性上皮样肉芽肿，在某些情况下还诱导出间质性炎症。这些病变持续存在，在90天组中更为明显；一些动物的肺部还出现了支气管周围炎症和坏死，并已蔓延至肺泡间隔。用炭黑处理的小鼠肺部正常，而用高剂量石英处理的小鼠肺部则显示出轻度至中度炎症。这些结果表明，在此处描述的测试条件下，在同等重量的基础上，如果碳纳米管进入肺部，它们的毒性比炭黑大得多，并且可能比石英更具毒性，而石英在慢性吸入暴露中被认为是一种严重的职业健康危害。
