Acute changes in the surface morphology of hamster tracheobronchial epithelium following benzo(a)pyrene and ferric oxide administration.

Acute changes in the surface morphology of hamster tracheobronchial epithelium were examined by scanning electron microscopy following intratracheal administration of ferric oxide or benzo(a)pyrene absorbed to ferric oxide. Multiple instillation of ferric oxide brought about a loss of ciliated cells and broad areas of abnormal, enlarged nonciliated cells with roughened or wrinkled surfaces. These were interpreted as areas of epithelial hyperplasia. Multiple intratracheal administrations of benzo(a)pyrene and ferric oxide caused similar changes and, in addition, produced squamous metaplasia and small foci of markedly abnormal protuberant cells. These findings are correlated with a pre viously reported observation obtained by transmission elec tron microscopy. The results suggest that scanning electron microscopy is useful in studies of the histogenesis of lung cancer.