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Effects of topical mitomycin on inner ear: a light and electron microscopic study
Hakan Cankaya1, Erol Egeli, Leyla Kuntsal
1Department of Otorhinolaryngology, Medical Faculty, Yüzüncü Yil University, Van, Turkey. hcankaya2@hotmail.com
Abstract:
Providing maintenance of myringotomy patency without use of ventilation tubes in the treatment of secretory otitis media has been one of the important study areas. For this reason, laser and Mitomycin C (MMC) are used together in experimental studies. But there has been no ultrastructural studies concerning whether leakage of MMC to middle ear during application of this procedure has an ototoxic effect or not and if so, to what extent. In this study, we searched the ultrastructural changes which occurred in the middle ear by direct applications of MMC to the middle ear for different time durations. The study was carried out over thirty adult guinea pigs without ear diseases. Bilateral myringotomy was performed and MMC was applied only to the right middle ear of each guinea pig. The first group received MMC once for 10 minutes, the second group received it once for 20 minutes, and the third group took it each day for 10 minutes during a one week period. The left ears of the samples were accepted as the control group. On the 8th day, sacrification was carried out. After electron and light microscopy examination, significant changes in the inner ear were observed in the third group though no significant change was observed for the first and the second groups. As a result it was concluded that the application of MMC to the middle ear once for a short duration causes no toxic effect on the inner ear.
Insights
Mitomycin C (MMC) applied to the middle ear for short durations did not cause inner ear toxicity. Repeated, prolonged application, however, led to significant ultrastructural changes in guinea pigs.
Area of Science:
- Otolaryngology
- Ototoxicology
- Regenerative Medicine
Background:
- Maintaining myringotomy patency without ventilation tubes is crucial for treating secretory otitis media.
- Laser and Mitomycin C (MMC) are explored for this purpose, but their ototoxic effects require investigation.
- Ultrastructural evidence regarding MMC's ototoxicity after middle ear application is lacking.
Purpose of the Study:
- To investigate the ultrastructural changes in the middle ear following direct application of Mitomycin C (MMC) for varying durations.
- To assess the ototoxic potential of MMC when applied to the middle ear in an experimental setting.
Main Methods:
- Thirty adult guinea pigs underwent bilateral myringotomy with MMC applied to the right middle ear.
- Three experimental groups received MMC for different durations: once for 10 minutes, once for 20 minutes, or daily for 7 days.
- Left ears served as controls; ultrastructural analysis was performed on day 8.
Main Results:
- No significant inner ear changes were observed in groups receiving a single MMC application (10 or 20 minutes).
- Significant ultrastructural changes were noted in the inner ear of the group receiving daily MMC application for one week.
- Control ears showed no adverse effects.
Conclusions:
- Single, short-duration applications of Mitomycin C (MMC) to the middle ear appear safe and non-ototoxic.
- Prolonged or repeated MMC application to the middle ear may induce ototoxicity.
- Further research is needed to establish safe protocols for MMC use in otologic procedures.