Miller B E, Dethloff L A, Gladen B C, Hook G E
Laboratory of Pulmonary Pathobiology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina.
Lab Invest. 1987 Nov;57(5):546-54.
Type II cell hyperplasia and hypertrophy were quantitated in the lungs of rats exposed to silica by using intratracheal injection. Hypertrophic type II cells were separated from normal type II cells by means of centrifugal elutriation of cells dispersed from the lungs by using protease. Type II cell hypertrophy was also quantitated, in situ, by measuring cell profile areas in lung sections. As a means of distinguishing between the hyperplastic and hypertrophic responses of type II cells we followed the progression of these two responses as a function of time and of dose. Seven, 14, and 28 days after a single intratracheal injection of silica (10 mg/rat), hypertrophic type II cells accounted for 33, 35, and 57% of the total type II cells recovered from the lungs. In contrast, hypertrophic type II cells accounted for less than 15% of the type II cells from control lungs. The appearance of hypertrophic type II cells was dose-related when examined 2 weeks after dosing; however, after only 1 week, the response of the type II cell appeared independent of dose. The hypertrophic response of type II cells could not be separated from the hyperplastic response according to either dose or time responses. These data support the hypothesis that in the lungs of silica-treated rats, the hypertrophic type II cell may be the proliferative type II cell. In addition, the hypertrophic type II cell appears to underlie the marked increases in surfactant levels seen in silica-treated lungs.
通过气管内注射，对暴露于二氧化硅的大鼠肺部的II型细胞增生和肥大进行了定量分析。利用蛋白酶将肺部分散的细胞进行离心淘析，从而将肥大的II型细胞与正常的II型细胞分离。还通过测量肺切片中细胞轮廓面积，对II型细胞肥大进行原位定量分析。作为区分II型细胞增生和肥大反应的一种方法，我们跟踪了这两种反应随时间和剂量的变化过程。在单次气管内注射二氧化硅（10毫克/只大鼠）后的第7、14和28天，肥大的II型细胞分别占从肺中回收的II型细胞总数的33%、35%和57%。相比之下，肥大的II型细胞在对照肺的II型细胞中所占比例不到15%。给药2周后检查发现，肥大的II型细胞的出现与剂量相关；然而，仅在1周后，II型细胞的反应似乎与剂量无关。根据剂量或时间反应，II型细胞的肥大反应无法与增生反应区分开来。这些数据支持了这样一种假说，即在经二氧化硅处理的大鼠肺部，肥大的II型细胞可能是增殖性II型细胞。此外，肥大的II型细胞似乎是经二氧化硅处理的肺部表面活性物质水平显著升高的原因。
