BACTERIAL CYTOLYSIN PERTURBS ROUND WINDOW MEMBRANE-PERMEABILITY BARRIER IN-VIVO - POSSIBLE CAUSE OF SENSORINEURAL HEARING-LOSS IN ACUTE OTITIS-MEDIA

The passage of radioiodinated streptolysin-O (SLO) and albumin through the round window membrane (RWM) was studied in vivo. When applied to the middle ear, SLO became quantitatively entrapped in this compartmen t and no passage to the cochlea occurred. However, flu of radioiodinat ed albumin through the toxin-damaged RWM was observed. We propose that the passage of noxious macromolecules, such as proteases, from a puru lent middle-ear effusion may be facilitated by pore-forming toxins, re sulting in cochlear damage and sensorineural hearing loss.