Roggli V L, George M H, Brody A R
Environ Res. 1987 Feb;42(1):94-105. doi: 10.1016/s0013-9351(87)80010-5.
Previous studies in this laboratory have demonstrated fiber clearance and dimensional changes in chrysotile asbestos using a rat inhalational model of short-term exposure. The purpose of the present study was to determine whether or not similar changes occurred in crocidolite asbestos fibers isolated from the lungs of rats at various intervals after termination of exposure. Fibers were recovered on a membrane filter using a sodium hypochlorite digestion-concentration technique, and the numbers and dimensions of the fibers assessed using scanning electron microscopy. The mass of crocidolite asbestos retained in the lung was then calculated. Of the respirable fraction, 19% was deposited in the lungs, and 25% of this amount was still present 1 month after exposure. These values are similar to the 23% deposition and 19% retention rates for chrysotile determined in our previous study. There was a progressive increase in mean fiber length with time postexposure (P less than 0.05), but no significant changes in the diameter of the population of crocidolite fibers retained in the lung. Thus it appears that the tendency for longer fibers to be retained within lung tissue is a characteristic shared by serpentine and amphibole asbestos fibers, whereas longitudinal splitting with progressive decrease in mean fiber diameter in vivo occurs primarily with the serpentine fibers.
本实验室之前的研究已利用大鼠短期吸入模型，证明了温石棉的纤维清除和尺寸变化。本研究的目的是确定在暴露终止后的不同时间段，从大鼠肺中分离出的青石棉纤维是否会发生类似变化。使用次氯酸钠消化浓缩技术在膜滤器上回收纤维，并使用扫描电子显微镜评估纤维的数量和尺寸。然后计算肺中保留的青石棉质量。在可吸入部分中，19%沉积在肺中，暴露1个月后，其中25%仍然存在。这些值与我们之前研究中确定的温石棉23%的沉积率和19%的保留率相似。暴露后平均纤维长度随时间逐渐增加（P小于0.05），但肺中保留的青石棉纤维群体的直径没有显著变化。因此，似乎较长纤维保留在肺组织内的趋势是蛇纹石和闪石石棉纤维共有的特征，而体内平均纤维直径随着纵向分裂逐渐减小主要发生在蛇纹石纤维中。
