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 previously reported observation obtained by transmission electron microscopy. The results suggest that scanning electron microscopy is useful in studies of the histogenesis of lung cancer.


Supported by Contract 69-2148 from the Lung Cancer Segment, Carcinogenesis, Division of Cancer Cause and Prevention, National Cancer Institute, NIH, Bethesda, Md.

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