Is Mesna safe in middle ear surgeries? An animal study

Mesna, a thiol-containing compound, assists in otological surgeries such as cholesteatoma and tympanosclerosis, adhesive otitis media and atelectatic ears by breaking down pathological tissues through its mucolytic properties, acting as a chemical dissector. In this study, the objective was to evaluate the ototoxic potential of 100% topical Mesna administration in the middle ear using an animal model.

Sixteen female albino guinea pigs were enrolled in the study. Final analysis was performed on twelve animals. The guinea pigs were randomly divided into two groups. Group 1 - six guinea pigs received 100% Mesna powder in one ear, while the other received powdered boric acid, a non-ototoxic control substance. Group 2 - six guinea pigs received 100% Mesna solution in one ear, while the other received saline solution, as a non-ototoxic control substance. Ototoxicity was assessed through auditory brainstem response (ABR) testing at baseline (postmyringotomy) and 4 weeks post-application and scanning electron microscopy (SEM) of cochlear hair cells approximately 2 months post-application.

No inflammation was observed in any ear canal. ABR measurements remained consistent between baseline and 4 weeks post-application. SEM analysis in all groups revealed no damage to inner or outer hair cells.

This study demonstrates that topical application of 100% Mesna, in both powder and solution forms, does not induce ototoxic effects in a guinea pig model. These findings support the safety of Mesna for middle ear use and may promote its broader adoption in otologic surgical practice.