Behavior of new type of rock wool (HT wool) in lungs after exposure by nasal inhalation in rats
Behavior of new type of rock wool (HT wool) in lungs after exposure by nasal inhalation in rats
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DOI：
10.1007/bf02897697
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发表时间：
2005-09-01
影响因子：
4.7
通讯作者：
Aizawa, Yoshiharu
中科院分区：
文献类型：
--
作者：
Kudo, Yuichiro;Shibata, Kaori;Aizawa, Yoshiharu
目的：以前类型的岩棉最近被高温棉（HT棉）所取代。高温岩棉具有Al2O3浓度较高、SiO2浓度较低、生物持久性较低、熔点较高的化学组成特征。为了评估HT羊毛（一种石棉替代品）的安全性，我们通过对大鼠进行仅鼻子吸入暴露研究，根据长度和纤维大小（长度和宽度）的纤维计数变化，检测了HT羊毛在肺部的生物持久性。方法：雄性Fischer 344大鼠以目标暴露浓度为30 mg/m(3)，每天连续暴露3小时，连续5天。暴露后不久、暴露后1、2、4周处死大鼠，低温焚烧肺组织。然后，使用相差显微镜分析肺中的纤维计数和大小。结果：暴露后4周肺部纤维计数明显低于基线值（暴露后不久）。根据近似曲线计算，所有纤维的半衰期为34天，超过20分钟的纤维的半衰期为11天。结论：暴露后4周，纤维的长度和宽度均明显减小，可能是由于纤维被肺泡巨噬细胞吞噬，或被黏毛运动排出体外，或被体液溶解所致。在未来的研究中，有必要检查纤维在肺部的长期持久性。
Objectives: Previous types of rock wool has been recently replaced with high-temperature wool (HT wool). HT wool is characterized by a chemical composition with a higher concentration of Al2O3 and a lower concentration of SiO2, lower biopersistence, and a higher melting point than previous types of rock wool. To evaluate the safety of HT wool, an asbestos substitute, we examined the biopersistence of HT wool in the lungs, based on changes in fiber count according to the length and fiber size (length and width), by performing a nose-only inhalation exposure study in rats.Methods: Male Fischer 344 rats were exposed to fibers at the target exposure concentration of 30 mg/m(3) continuously for 3 hours daily for 5 consecutive days. Rats were sacrificed shortly after exposure, and 1, 2, and 4 weeks after exposure, and their lung tissues were incinerated at a low temperature. Then, fiber counts and sizes in the lungs were analyzed using a phase contrast microscope.Results: The fiber count in the lungs 4 weeks after exposure significantly decreased from the baseline value (shortly after exposure). The half-life of fibers calculated from the approximation curve was 34 days for all fibers and 11 days for fibers longer than 20 pm.Conclusions: Both the length and width significantly decreased 4 weeks after exposure, probably because fibers were ingested by alveolar macrophages, discharged to outside of the body by mucociliary movement, or lysed by body fluid. In future studies, it is necessary to examine the long-term persistence of fibers in the lungs.