Cochlear Pathology in Experimental Otitis Media with Effusion ofGuinea Pig Caused by Endotoxin / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Injection of endotoxin into the middle ear of experimental animals results in otitis media with effusion and transient reversible hearing loss, which occurs in the higher concentration of endotoxin than the concentration found in human middle ear effusion. The purpose of this study was to investigate the histopathologic changes of the cochlea in guinea pigs with experimental otitis media with effusion induced by E.coli endotoxin. MATERIALS AND METHODS: Concentrations of lipopolysaccharides (LPS) from E.coli, such as 0.1 mg/ml, 1 mg/ml, and 10 mg/ml, were instillated into the middle ear cavity of 30 normal guinea pigs. Histopathologic changes of the cochlea were observed at 1 week after endotoxin instillation, using both light and electron microscope. Six normal guinea pigs were used as a control group whose middle ears were instillated with the physiologically sterile saline. RESULTS: There were deformation in the organ of Corti, partial loss of stereocilia in the hair cells, and vacuolation in stria vascularis at a concentration of 10 mg/ml lipopolysaccharides from E. coli. Mild morphologic abnormality of the cochlea was observed at the concentrations of 1 mg/ml and 0.1 mg/ml. CONCLUSION: A higher concentration of LPS in the middle ear cavity may produce severe inner ear damage, possibly resulting in the sensorineural hearing loss.