Pulmonary fibrogenesis after three consecutive inhalation exposures to chrysotile asbestos.

Journal Article (Journal Article)

Previously, this laboratory developed a model of asbestos-induced pulmonary fibrogenesis in rats and mice after a brief (1 to 3-h) inhalation exposure. However, typical human environmental exposures would be repeated, although at lower concentrations than those used in our animal model. Here we have extended this model to encompass repeated exposures and consequent long-term effects. Groups of rats were exposed to chrysotile aerosol (10 mg/m3) for 3- to 5-h periods over 3 consecutive days. Lung fiber burden and pathologic features were studied for as long as 6 mo after exposure. We found that many of the longest (> or = 8 microm) fibers were retained in the lung for at least 6 mo, whereas shorter fibers were cleared more rapidly. The three exposures to chrysotile caused a large increase in DNA synthesis in the epithelium of terminal bronchioles and more proximal airways. When compared with a single exposure, the triple exposure caused an enhanced inflammatory response as well as a prolonged period of increased DNA synthesis in the proximal alveolar region. Hyperplastic, fibrotic lesions subsequently developed in the same region and persisted for at least 6 mo after exposure. These findings will be valuable in directing future studies of the mechanisms of pulmonary fibrosis in this model.

Full Text

Duke Authors

Cited Authors

  • Coin, PG; Osornio-Vargas, AR; Roggli, VL; Brody, AR

Published Date

  • November 1996

Published In

Volume / Issue

  • 154 / 5

Start / End Page

  • 1511 - 1519

PubMed ID

  • 8912773

International Standard Serial Number (ISSN)

  • 1073-449X

Digital Object Identifier (DOI)

  • 10.1164/ajrccm.154.5.8912773


  • eng

Conference Location

  • United States