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Morphological and electron microscopic effects of mitomycin C inhalation in experimentally induced laryngeal fibrosis in dogs




This study was carried out to investigate the morphological and ultrastructural effects of mitomycin C in the inhalational form on induced laryngeal tissue injuries and fibrosis.

Materials and methods

This study was carried out on 17 cross-breed clinically healthy dogs. Three dogs were included in a normal control group. The rest of the 14 dogs were subjected to induction of laryngeal fibrosis and assigned randomly to two equal groups: one treated with inhalational mitomycin C and the other was an untreated control group. Tissue biopsies were studied after H&E and Masson’s trichrome stains, whereas other pieces were examined by electron microscopy.


Epithelial ulceration with marked inflammatory infiltration, edema, and congestion was evident in all experimented dogs. There was a significant difference in epithelial hyperplasia between the treated and the untreated groups; it was markedly reduced in the treated group. The untreated group showed extensive well-organized fibrosis that was significantly increased compared with the other groups. Results were confirmed by electron microscopy.


Inhalation of mitomycin C has a potent antifibrotic effect through decreasing the activity of fibroblast evident by the decrease in both the size of fibroblast and the density of the intrafibroblast endoplasmic reticulum.


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Corresponding author

Correspondence to Mohamed T. El Tabbakh MD.

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Conflicts of interest

None declared.

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El Tabbakh, M.T., Zagholol, M.M.H.M., Hinnis, A.R. et al. Morphological and electron microscopic effects of mitomycin C inhalation in experimentally induced laryngeal fibrosis in dogs. Egypt J Otolaryngol 30, 126–131 (2014).

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  • electron microscope
  • inhalational mitomycin C
  • laryngeal fibrosis