Morphological Changes of Endolymphatic Sac after Gentamicin Injection to Chick Embryo

Lee, Ju Hyoung; Kim, Dong Young; Lee, Youn Kyu; Han, Gyu Cheol; Ha, Jong Su; Cha, Heung Eog

Abstract

BACKGROUND AND OBJECTIVES
Gentamicin, which is known to have potential toxic effect to the inner ear, causes functional disturbance by destroying the inner ear at a concentration above a certain level. The purpose of this study was to identify morphological changes in the endolymphatic sac after gentamicin injection using chick embryo and the degree of changes according to different concentration of gentamicin. MATERIALS AND METHOD: The same breed of chicken (Gallus domesticus) was chosen and artificial growth incubator was used to germinate the eggs. Increasing the concentration of gentamicin at the same rate (10, 20, 30, 40 mg/ml), we injected it into the yolk sac of chicken and observed the morphological changes in the embryonic sac by light microscope. RESULTS: As the concentration of gentamicin increased, the size of the endolymphatic sac increased and the thickness and contour of sac wall changed. Especially, the inner membrane thinned down greatly. CONCLUSION: In this research, we confirmed that endolymphatic sac is affected by gentamicin in proportion to its concentration. Especially, considering that inner membrane epithelial cells play an important role in the absorption of endolymph, we suggest that the ototoxicity of gentamicin causes the disturbance in the absorption of endolymph, which may cause endolymphatic hydrops.