Short- and long-term effects of irradiation on laryngeal mucosa of the rat

Although radiotherapy is often used to treat laryngeal carcinoma, there is little information on the effects of this treatment on laryngeal structures . Rats were irradiated to the head and neck region and the larynges were st udied by light and electron-microscopy and immunohistochemistry. Ten days a fter irradiation, a change in the ultrastructural appearance of the granule s of the subglottic glands was observed. Substance P-, bombesin- and enkeph alin-like immunoreactivity was increased in local ganglionic cells and glan dular nerve fibres. The mast cells were reduced in number. At examination 4 -6 months after irradiation, there were no obvious differences compared wit h controls concerning mast-cell numbers and neuropeptide expression. The ul trastructural changes seen in the subglottic glands remained to some extent . The results show that structural changes in the subglottic glands occur c oncomitantly with an increased expression of certain neuropeptides in the i nnervation of these glands, which implies a relationship between these two parameters. The mast cells respond drastically to irradiation, but in the l ong run, regeneration of these cells occurs.