Wehner A P, Dagle G E, Cannon W C, Buschbom R L
Department of Biology, Battelle, Pacific Northwest Laboratories, Richland, Washington 99352.
Environ Res. 1978 Dec;17(3):367-89. doi: 10.1016/0013-9351(78)90041-5.
Two groups of 96 male Syrian golden hamsters were exposed to respirable asbestos cement aerosol at concentrations of approximately 1 and approximately 10 micrograms/liter, respectively, 3 hours/day, 5 days/week. Average fiber counts ranged from 5 to about 120 fibers/cm3. Each group was randomly divided into six subgroups of 16 animals. The first subgroup was sacrificed after 3 months of exposure, the second after 6 months, and the third after 15 months. The fourth subgroup was withdrawn from exposure after 3 months, observed for an additional 3 months, and then sacrificed. The fifth and sixth subgroups were withdrawn after 3 and 6 months of exposure, respectively, and maintained for observation up to the 15-month exposure point of the third subgroup at which time all surviving animals were sacrificed. All other experimental procedures were similar to those delineated in a previous publication describing the development of an animal model, techniques, and an exposure system for asbestos cement dust inhalation (A. P. Wehner, G. E. Dagle, and W. C. Cannon, 1978, Environ. Res. 16, 393-407). The asbestos cement exposures had no significant effect on body weight and mortality of the animals. Higher aerosol concentration and longer exposure times increased the number of macrophages and ferruginous bodies found in the lungs of the exposed animals. Recovery periods had no effect on the incidence of macrophages and ferruginous bodies. The incidence of very slight to slight fibrosis in the animals sacrificed after 15 months of exposure shows a significant (P less than 0.01) trend when the untreated control group and the 1 and 10 microgram/liter dose level groups are compared, indicating a dose-response relationship. Development of minimal fibrosis continued in animals withdrawn from exposure. No primary carcinomas of the lung and respiratory tract and no mesotheliomas were found.
将两组各96只雄性叙利亚金仓鼠分别暴露于浓度约为1微克/升和约10微克/升的可吸入石棉水泥气溶胶中,每天暴露3小时,每周暴露5天。平均纤维计数范围为5至约120根/立方厘米。每组随机分为六个亚组,每组16只动物。第一个亚组在暴露3个月后处死,第二个亚组在6个月后处死,第三个亚组在15个月后处死。第四个亚组在暴露3个月后停止暴露,再观察3个月,然后处死。第五和第六个亚组分别在暴露3个月和6个月后停止暴露,并维持观察至第三个亚组的15个月暴露点,此时所有存活动物均被处死。所有其他实验程序与之前一篇描述动物模型、技术以及石棉水泥粉尘吸入暴露系统的出版物中所描述的相似(A.P.韦纳、G.E.达格尔和W.C.坎农,1978年,《环境研究》16卷,393 - 407页)。石棉水泥暴露对动物的体重和死亡率没有显著影响。更高的气溶胶浓度和更长的暴露时间增加了暴露动物肺部发现的巨噬细胞和含铁小体的数量。恢复期对巨噬细胞和含铁小体的发生率没有影响。当比较未处理的对照组与1微克/升和10微克/升剂量水平组时,暴露15个月后处死的动物中非常轻微至轻微纤维化的发生率呈现出显著(P小于0.01)趋势,表明存在剂量反应关系。停止暴露的动物中仍继续发展出轻微纤维化。未发现原发性肺癌和呼吸道癌,也未发现间皮瘤。