Warheit D B, McHugh T A, Hartsky M A
Central Research and Development, Du Pont Haskell Laboratory for Toxicology and Industrial Medicine, Newark, Delaware, USA.
Scand J Work Environ Health. 1995;21 Suppl 2:19-21.
Pulmonary responses in rats were compared after short-term inhalation exposure to polymorphs of silica dust. Groups of CD rats were exposed 6 h a day for 3 d to crystalline silica or amorphous silica. Another group was exposed to Ludox colloidal silica for 6 h a day, 5 d a week for two or four weeks. Thereafter the groups were killed, and the lungs washed at several postexposure times. The crystalline silica produced persistent pulmonary inflammatory responses characterized by neutrophil recruitment and consistently elevated biomarkers of cytotoxicity in bronchoalveolar lavage fluids, and progressive histopathological lesions were observed within one month of the exposure. Amorphous silica produced a transient pulmonary inflammatory response, and Ludox elicited transient pulmonary inflammatory responses at 50 or 150 mg center dot m-3 but not at 10 mg center dot m-3. After three months most of the biochemical values of the Ludox-exposed animals had returned to the control level. These results demonstrate that crystalline silica dust is more potent in producing pulmonary toxicity when compared with amorphous or colloidal silica particles.
在大鼠短期吸入二氧化硅粉尘多晶型物后，对其肺部反应进行了比较。将几组CD大鼠每天暴露6小时，持续3天，分别接触结晶二氧化硅或无定形二氧化硅。另一组大鼠每天暴露于Ludox胶体二氧化硅6小时，每周5天，持续两周或四周。此后处死这些组的大鼠，并在暴露后的几个时间点对肺部进行冲洗。结晶二氧化硅产生持续的肺部炎症反应，其特征是中性粒细胞募集，支气管肺泡灌洗液中的细胞毒性生物标志物持续升高，并且在暴露后一个月内观察到进行性组织病理学病变。无定形二氧化硅产生短暂的肺部炎症反应，Ludox在50或150 mg·m⁻³时引起短暂的肺部炎症反应，但在10 mg·m⁻³时未引起。三个月后，暴露于Ludox的动物的大多数生化值已恢复到对照水平。这些结果表明，与无定形或胶体二氧化硅颗粒相比，结晶二氧化硅粉尘在产生肺部毒性方面更强效。
