[Morphological observations of the medial olivocochlear efferents in gerbils with chronic gentamicin ototoxicity].
OBJECTIVE
To determine the possible involvement of the medial olivocochlear efferents (MOC) in chronic aminoglycoside ototoxicity, the morphological changes of the MOC efferents in the cochlea of Mongolian gerbils and their correlations with the impairment of the outer hair cells (OHCs) were observed.


METHODS
The animals were given gentamicin in a dose of 150 mg/kg a day for 10 days. The distributions and densities of the MOC efferents were examined using the modified histochemical staining for acetylcholinesterase (AChE) and the numbers of OHCs were numerated with toluidine blue and Ehrlich haematoxylin staining on the surface preparation.


RESULTS
Significant damage to the MOC fibers and terminals as well as OHCs was noted in the basal turn of the cochlea, especially in those animals examined in 7th and 11th week after the gentamicin administration. The site of the greatest impairment of OHCs was consistent with that of the MOC efferents.


CONCLUSIONS
The results suggested that damage to the MOC efferents might play an important role in gentamicin-induced impairment of OHCs.
Xie
D
D
Department of Otorhinolaryngology, Second Affiliated Hospital of Hunan Medical University, Changsha 410011.
Guo
Y
Y
Wu
W
W
D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D003051:Cochlea / Q000294:innervation; D003056:Cochlear Nerve / Q000187:drug effects / Q000473:pathology*; D005260:Female; D005839:Gentamicins / Q000633:toxicity*; D005849:Gerbillinae; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects / Q000473:pathology*; D008297:Male; D009476:Neurons, Efferent / Q000187:drug effects / Q000473:pathology*; D009847:Olivary Nucleus / Q000187:drug effects / Q000473:pathology; D013194:Staining and Labeling / Q000379:methods
D000900:Anti-Bacterial Agents; D005839:Gentamicins