Antibiotics and Sensorineural Interactions In vitro Studies

Abstract

Organ culture of the embryonic inner ear of the mouse results, under normal conditions, in a good morphological morphogenesis and cytodifferentiation of individual cells and tissues. Organ culture is performed during a period corresponding to the embryonic development in vivo. Continuing the culture period causes a deterioration of the organ culture explant. Only a minor portion of the total innervation of vestibular and cochlear parts of the labyrinth occurs prior to birth. Low dose exposure (1–10 μg/ml) of ototoxic antibiotics in the culture medium causes a primary morphologic damage of vestibular and cochlear hair cells and a markedly reduced number of nerve fibers and statoacoustic ganglion cells. Likewise the ingrowing nerve fibers are even more vulnerable to aminoglycoside antibiotics than the hair cells. Such a drug exposure in the in vitro system confirms (by a chemical deprivation of nerve fiber ingrowth to developing hair cells) that hair cell differentiation occurs at least initially independent of morphologic contact with ingrowing nerve fibers as was earlier shown using a mechanical excision of the statoacoustic ganglion.

Key Words:

• inner ear
• in vitro
• hair cell
• nerve fiber
• drug exposure