Effect of intratympanic mitomycin C on the development of cholesteatoma and otitis media in rats.

To determine whether the administration of mitomycin C prevents propylene glycol exposure from inducing middle-ear cholesteatoma and otitis media, in a rat model. Twenty-four Wistar rats underwent intratympanic injections on days 1, 8 and 15, via the tympanic membrane pars tensa, in both the right and left ears. The right ear injection solution contained 50 per cent propylene glycol, gentamicin and saline (0.9 per cent), while the left ear solution contained 50 per cent propylene glycol, gentamicin and mitomycin C. Animals were sacrificed and examined. There were statistically significant differences between the control and experimental groups for tympanic bulla mucosal thickness (p = 0.004) but not for tympanic membrane thickness (p = 0.371), otomicroscopic findings (p = 0.262), or the presence of exudate (p = 0.125), fibrosis (p = 1.000) or cholesteatoma (p = 0.687). Intratympanic mitomycin C was ineffective in preventing middle-ear cholesteatoma and otitis media in this rat model.