Using in vitro iron deposition on asbestos to model asbestos bodies formed in human lung.
Using in vitro iron deposition on asbestos to model asbestos bodies formed in human lung.
复制标题
利用石棉上的体外铁沉积来模拟人肺中形成的石棉体。
DOI：
10.1021/tx000025b
复制
发表时间：
2000
影响因子：
4.1
通讯作者：
Aust,AE
中科院分区：
文献类型：
--
作者：
Shen,Z;Bosbach,D;HochellaJr,MF;Bish,DL;WilliamsJr,MG;Dodson,RF;Aust,AE
最近的研究表明，铁是石棉化学活性的重要因素，并可能在其生物效应中发挥关键作用。石棉、青石棉和铁石棉的致癌作用最强，它们的晶体结构中含有高达27%的铁。这些矿物质被吸入后可以获得更多的铁，从而形成石棉体。本文报道了一种在体外将铁沉积在石棉纤维上的方法，该方法产生的铁沉积形式与从人肺中取出的石棉体上观察到的铁沉积形式相同。青石棉和铁石棉在FeCl2或FeCl3溶液中孵育2 h，青石棉在FeCl2或FeCl3溶液中孵育14天，铁石棉在FeCl3溶液中孵育14天，评价长期结合的效果。被纤维结合的铁的量是通过用螯合剂亚铁锌来测量孵化液中剩余的铁的量来确定的。在进行了铁负载后，还使用X射线光电子能谱(XPS)检查了纤维表面铁含量的增加。XPS分析表明，负载Fe(II)和Fe(III)的青石棉表面铁含量增加，而仅负载Fe(III)的铁石棉表面铁含量增加。此外，原子力显微镜显示，铁闪石在1 mM FeCl3溶液中孵育2 h后，与未经处理的纤维相比，其表面形貌非常粗糙，进一步证明了Fe(III)在纤维表面的积累。用X射线衍射仪对长期负载Fe(III)的青石棉和铁铁石粉进行了分析，表明形成了结晶较差的水合氧化铁--水合铁水合铁。X射线衍射仪还显示，在取自人肺的铁粒石芯石棉体中含有亚铁水合物。俄歇电子能谱(AES)证实，铁和氧是石棉体表面仅有的组成元素，尽管俄歇电子能谱不能检测到H，而且可能也存在H。综上所述，本文报道的数据表明，在本研究所用的条件下，Fe(II)结合可能是由于纤维表面的离子交换，可能是与Na的离子交换，而Fe(III)结合在纤维上形成亚铁水合物。因此，在体外仔细负载Fe(III)的纤维可能是一个特别合适和有用的模型，用于研究与石棉体相关的化学特性及其在生物系统中的相互作用潜力。
Recent studies have shown that iron is an important factor in the chemical activity of asbestos and may play a key role in its biological effects. The most carcinogenic forms of asbestos, crocidolite and amosite, contain up to 27% iron by weight as part of their crystal structure. These minerals can acquire more iron after being inhaled, thereby forming asbestos bodies. Reported here is a method for depositing iron on asbestos fibers in vitro which produced iron deposits of the same form as observed on asbestos bodies removed from human lungs. Crocidolite and amosite were incubated in either FeCl2or FeCl3solutions for 2 h. To assess the effect of longer-term binding, crocidolite was incubated in FeCl2or FeCl3and amosite in FeCl3for 14 days. The amount of iron bound by the fibers was determined by measuring the amount remaining in the incubation solution using an iron assay with the chelator ferrozine. After iron loading had been carried out, the fibers were also examined for the presence of an increased amount of surface iron using X-ray photoelectron spectroscopy (XPS). XPS analysis showed an increased amount of surface iron on both Fe(II)- and Fe(III)-loaded crocidolite and only on Fe(III)-loaded amosite. In addition, atomic force microscopy revealed that the topography of amosite, incubated in 1 mM FeCl3solutions for 2 h, was very rough compared with that of the untreated fibers, further evidence of Fe(III) accumulation on the fiber surfaces. Analysis of long-term Fe(III)-loaded crocidolite and amosite using X-ray diffraction (XRD) suggested that ferrihydrite, a poorly crystallized hydrous ferric iron oxide, had formed. XRD also showed that ferrihydrite was present in amosite-core asbestos bodies taken from human lung. Auger electron spectroscopy (AES) confirmed that Fe and O were the only constituent elements present on the surface of the asbestos bodies, although H cannot be detected by AES and is presumably also present. Taken together for all samples, the data reported here suggest that Fe(II) binding may result from ion exchange, possibly with Na, on the fiber surfaces, whereas Fe(III) binding forms ferrihydrite on the fibers under the conditions used in this study. Therefore, fibers carefully loaded with Fe(III) in vitro may be a particularly appropriate and useful model for the study of chemical characteristics associated with asbestos bodies and their potential for interactions in a biosystem.