Ultrastructure of the lung in the rat following exposure to crocidolite asbestos and quartz

Abstract

Lung tissue from rats that had inhaled U.I.C.C [International Union against cancer] crocidolite asbestos or quartz particles showed thickening of the interstitial tissue and the presence of collagen fibers. Aggregates of macrophages in the alveolar spaces were a dominant feature of all the sections examined from asbestos exposed rats. According to the ultrastructural studies described here, all the macrophages were mature cells, indicating that the ingested crocidolite asbestos was non-toxic. Lung sections of rats exposed to quartz particles were significantly different. Single cells were found in the alveolar spaces and many macrophages showed a characteristic pattern of vacuole formation. Other cells contained intracellular membranous lamellated bodies, similar to those found in type II pneumocytes. Cells containing lamellated bodies were also found in the interstitial tissue. The 2 mineral dusts have quite different biological effects on the macrophage and the development of pulmonary fibrosis may, to some extent, be caused by a different mechanism in each instance.