中国典型温石棉与主要人工代用纤维的致突变性及其机理研究

China is the largest cosumer of chrisotile and the second largest manufacturer in the world,more than 1 million people are exposuring to chrysotile in China. Its safety in use has been debated for years. Plus, the artificial substitute fibers as promoted by many western countries have been shown to be unsafe. Four kinds of chrysotile fibres from main mining area in China and three kinds of artificial substitute fibers are been chosen as research object. The relation of mutagenicity and surface properties, biological persistence of the chrysotile and artificial substitute fibers from different regions will be researched in this project by using the techniques of spectrum, electron microscope technique, and molecular biology. Its intention is to study the mutagenicity of chrysotile fibers in vitro and in vivo from molecular level,proven the effect of the fibers on expression of tumor-associated gene and protein,clarigy the rolemigration and transformation of insoluble elements such as Si, price change elements such as Fe in chrysotile and artificial substitute fibers through biological effect in vivo.This project tries to indicate the essence of surface activity-biology activity-biology persistence- mutagenicity- environment safety of chrysotile fiber and artificial substitute fibers by analyzing the mineral structure features, surface properties, biology attribute and biology reactivity. Finally, we evaluate the mutagenicity and safety of chrysotile fiber as well as artificial substitute fibers, which would lay the groundwork for establishing the safety evaluation system and standard of chrysotile fiber and artificial substitute fibers.

中国是全球温石棉最大消费国和第二大生产商，全国超过1百万人被职业暴露，但国际上对温石棉的使用安全性一直存在较大争议，西方国家提倡的代用纤维也被证明并不安全。本项目以我国四大矿区的典型温石棉和三种人工代用纤维作为研究对象，利用光谱、波谱、电镜及分子生物技术研究我国不同产地温石棉及人工代用纤维表面特性和生物持久性等与其致突变性的关系，旨在从分子水平观察纤维表现出的体内外致突变性，探明纤维对肿瘤相关基因及蛋白表达的影响，阐明温石棉及人工代用纤维难溶元素如Si、变价元素如Fe等通过生物作用在体内发生迁移与转化的方式。本研究试图从矿物的结构、表面特性、生物属性与生物反应性来揭示温石棉及人工代用纤维的表面活性-生物活性-生物持久性-致突变性-环境安全性之间的本质。研究结果可望为温石棉及其代用纤维安全评价体系建立及标准的制定奠定基础。

为评价中国典型温石棉与主要人工代用纤维的致突变性并进一步探究其致突变机理，以我国四大矿区（青海茫崖、甘肃阿克塞，陕西陕南和四川新康）的温石棉及三种代用纤维（玻璃纤维、岩棉纤维及陶瓷纤维）为研究对象，分析其形貌特征、粒径分布和表面特性，通过体外细胞毒性实验，从基因突变、DNA损伤和染色体畸变来评价其致突变性，并初步探讨其作用机制；采用非暴露式气管滴注法建立典型温石棉及人工代用纤维的Wistar大鼠致突变性动物模型，制备Wistar大鼠肺组织病理切片并进行形态学观察，对比分析细胞内氧化还原物质的变化情况，检测肺组织癌基因及抑癌基因、肿瘤特异相关蛋白的表达，从分子生物学水平探讨中国典型温石棉与主要人工代用纤维表面特性和生物持久性等与其致突变性的关系及作用机制。.研究结果表明：（1）超细化制备的四种温石棉及三种代用纤维平均粒径均＜5 μm，四种温石棉的主要物相是斜纤蛇纹石，三种代用纤维主要为无机物。（2）温石棉及代用纤维均具有一定的遗传毒性，可诱导细胞质内出现微核、DNA损伤和染色体畸变。（3）四种温石棉及三种代用纤维均可抑制细胞存活率，诱导细胞凋亡和周期阻滞，其诱导能力大小依次为：茫崖>玻纤>岩棉>阿克塞>新康>陶纤>陕南。（4）温石棉及代用纤维染毒后可使Wistar大鼠的肺组织表现出不同方式及程度的病理变化，并抑制其抑癌基因P16、P53的表达，促进原癌基因C-jun、C-fos、Survivin和Bcl-2的表达，尤以染毒3个月最为显著。.本课题的研究结果可为我国温世棉及代用纤维的使用提供安全性参考，并可对其安全评估体系的建立及标准的制定提供决策依据。