Vacek P M, Hemenway D R, Absher M P, Goodwin G D
Department of Medical Biostatistics, University of Vermont, Burlington 05405.
Fundam Appl Toxicol. 1991 Oct;17(3):614-26. doi: 10.1016/0272-0590(91)90211-l.
The movement of inhaled silicon dioxide particles was studied by measuring the amounts in alveolar fluid and cells, lung tissue, and lymphoid tissue during the 6 months following short-term aerosol exposure of Fischer 344 rats. A variety of first-order compartmental models were fit to data from nine exposure experiments to identify the most feasible biologic pathways for the transfer of material among these sites and out of the body. A multivariate least-squares approach was used to simultaneously fit the data from several compartments. The results indicate that transfer between alveolar cells and lung tissue occurs in both directions, suggesting that silica can reenter the alveolar space from the lung tissue. This feature has not been included in previously published models. The results also indicate that transfer from lung tissue to the mediastinal lymph nodes and thymus is indirect; there are one or more unidentified extrapulmonary compartments that receive silica from the lung. Rates of transfer among compartments were dependent on mineral type (quartz or cristobalite), heat treatment, and exposure dose. There was no evidence for direct clearance from the alveolar space via the tracheobronchial tract.
通过测量短期气溶胶暴露后6个月内Fischer 344大鼠肺泡液和细胞、肺组织及淋巴组织中的二氧化硅颗粒量，研究了吸入二氧化硅颗粒的运动情况。将多种一级房室模型与来自9个暴露实验的数据进行拟合，以确定物质在这些部位之间转移并排出体外的最可行生物学途径。采用多元最小二乘法同时拟合来自多个房室的数据。结果表明，肺泡细胞与肺组织之间的转移是双向的，这表明二氧化硅可以从肺组织重新进入肺泡腔。这一特征在先前发表的模型中并未包含。结果还表明，从肺组织到纵隔淋巴结和胸腺的转移是间接的；存在一个或多个未明确的肺外房室从肺接收二氧化硅。房室之间的转移速率取决于矿物类型（石英或方石英）、热处理和暴露剂量。没有证据表明通过气管支气管途径可直接从肺泡腔清除。
