Pulmonary effects and biopersistence of deposited silicon carbide whisker after 1-year inhalation in rats
Pulmonary effects and biopersistence of deposited silicon carbide whisker after 1-year inhalation in rats
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DOI：
10.1080/08958370601051784
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发表时间：
2007-01-15
影响因子：
2.1
通讯作者：
Tanaka, Isamu
中科院分区：
文献类型：
--
作者：
Akiyama, Izumi;Ogami, Akira;Tanaka, Isamu
碳化硅晶须（SiCW）是一种耐用的石棉替代品。为了阐明SiCW的生物持久性、沉积胡须几何构型的变化以及潜在的致癌性和致纤维化性，42只Wistar雄性大鼠经吸入暴露于SiCW，6 h/d，5d/wk，持续1年。质量中值空气动力学直径（几何标准偏差，GSD）、几何平均纤维直径（GSD）和几何平均纤维长度（GSD）分别为2.4 μ m（2.4）、0.5 μ m（1.5）和2.8 μ m（2.3）。每日平均暴露浓度为2.6 +/- 0.4 mg/m3（98 +/- 19纤维/ml），大鼠在暴露后第6天和第3、6和12个月被处死。在暴露后6天，通过X射线衍射法测定的沉积在每只大鼠肺中的SiCW量为5.3 +/- 1.4 mg。根据6天和3、6和12个月时沉积的SiCW计算，生物半衰期（BHT）为16个月。BHT比正常生理清除时间更长。在吸入后12个月的清除过程中，每次处死时肺中SiCW的直径没有变化。而SiCW在肺内的滞留时间随清除时间的延长而延长，尤其是6个月后。组织病理学检查显示，2只大鼠在暴露后1年出现支气管肺泡增生（BAH），聚集的SiCW周围出现严重的纤维化变化。
Silicon carbide whisker (SiCW) is a durable asbestos substitute. To clarify the biopersistence, the changes of geometrical configurations of deposited whiskers, and potential carcinogenicity and fibrogenicity, 42 Wistar male rats were exposed to SiCW for 6 h/day, 5 days/wk for 1 yr by inhalation. The mass median aerodynamic diameter (geometric standard deviation, GSD), the geometric mean fiber diameter (GSD), and the geometric mean fiber length (GSD) were 2.4 mu m (2.4), 0.5 mu m (1.5) and 2.8 mu m (2.3), respectively. The daily average exposure concentrations were 2.6 +/- 0.4 mg/m(3) (98 +/- 19 fibers/ml) and the rats were sacrificed at 6 days and 3, 6, and 12 mo after the exposure. The SiCW amount deposited in each rat lung at 6 days after the exposure, determined by an x-ray diffraction method, was 5.3 +/- 1.4 mg. The biological half-time (BHT) was 16 mo calculated from the deposited SiCW at 6 days and 3, 6, and 12 mo. The BHT was more prolonged than normal physiological clearance. The diameter of SiCW in the lung at each sacrificed time during 12 mo of clearance after the inhalation did not change. However, as for the length of SiCW in the lung, longer SiCW tended to be retained in the lung as the clearance time increased, especially after 6 mo. The histopathological examination revealed bronchoalveolar hyperplasia (BAH) in 2 rats at 1 yr after the exposure and severe fibrotic changes around aggregated SiCW.