Greenspan B J, Morrow P E, Ferin J
Department of Biophysics, University of Rochester Medical Center, NY 14642.
Exp Lung Res. 1988;14(4):491-9. doi: 10.3109/01902148809087823.
This study deals with the hypothesis that the lymphatic uptake of particles from the lung parenchyma increases when phagocytosis by pulmonary macrophages is inhibited. Cadmium chloride was chosen as the toxicant to inhibit phagocytosis and was administered as an aerosol to rats at concentrations of 1.5 mg Cd/m3 (mass median aerodynamic diameter = 0.4 micron, sigma g = 1.4) and 5.0 mg Cd/m3 (MMAD = 0.4 micron, sigma g = 1.6), each for 30 min. Control animals were exposed to a saline aerosol. Lung clearance and lymphatic uptake were assayed after exposing the cadmium-exposed rats to titanium dioxide (TiO2) dust at concentrations of 12-15 mg/m3 (MMAD = 1.0 micron, sigma g = 2.3) for 6 h. Preexposure to 5 mg Cd/m3 decreased the initial deposition of TiO2 by 40% compared to a saline preexposure. Although the overall clearance of TiO2 from the lungs was not different in the cadmium-exposed animals, the lymph node burden was 2.7 times higher in the CdCl2-exposed animals than in the controls. Exposures to 1.5 mg Cd/m3 had no effect on lung clearance or lymphatic uptake of TiO2. When TiO2 exposure preceded a 5.0 mg Cd/m3 exposure, the results were similar; i.e., more TiO2 was found in the lymph nodes of the animals. This study supports the concept that lymphatic uptake of dust particles increases when phagocytosis by alveolar macrophages is decreased.
当肺巨噬细胞的吞噬作用受到抑制时，肺实质中颗粒的淋巴摄取会增加。选择氯化镉作为抑制吞噬作用的毒物，以1.5毫克镉/立方米（质量中位空气动力学直径 = 0.4微米，几何标准差 = 1.4）和5.0毫克镉/立方米（质量中位空气动力学直径 = 0.4微米，几何标准差 = 1.6）的浓度分别给大鼠雾化吸入30分钟。对照动物暴露于盐雾气溶胶中。在将暴露于镉的大鼠暴露于浓度为12 - 15毫克/立方米（质量中位空气动力学直径 = 1.0微米，几何标准差 = 2.3）的二氧化钛（TiO₂）粉尘6小时后，测定肺清除率和淋巴摄取。与盐水预暴露相比，预先暴露于5毫克镉/立方米使TiO₂的初始沉积减少了40%。尽管在暴露于镉的动物中，TiO₂从肺中的总体清除率没有差异，但暴露于CdCl₂的动物的淋巴结负荷比对照组高2.7倍。暴露于1.5毫克镉/立方米对TiO₂的肺清除率或淋巴摄取没有影响。当TiO₂暴露先于5.0毫克镉/立方米暴露时，结果相似；即，在动物的淋巴结中发现了更多的TiO₂。本研究支持这样一种观点：当肺泡巨噬细胞的吞噬作用降低时，粉尘颗粒的淋巴摄取会增加。
