Permeability of the round window membrane of guinea pigs in acute suppurative otitis media

Acute suppurative otitis media of guinea pigs had been induced by inoculation of Staphylococcus aureus in the bulla. The permeability of the round window membrane to endotoxin was investigated by detecting endotoxin of the perilymph, applied to the round window using limulus amebocyte lysate test. It was found that endotoxin could pass through round window membranes of animals. With inflammation of middle ear, the permeability of the round window membrane to endotoxin was increased. These results suggest that bacterial toxins and the consequential migration of chemical inflammatory mediators might act as promoting factors of round window membrane permeability