Cochlear pathology induced by styrene.
Hair cells, spiral fibers and spiral ganglion cells (SGCs) coming from cochleae of styrene-treated Long-Evans rats were counted in order to assess the extent and location of the cochlear injury after the solvent inhalation. If the hair cells, and more specifically the outer hair cells (OHCs), were undoubtedly the first targets of inhaled styrene, the histological results of the present study would seem to indicate that neurons of the spiral ganglion were also injured with increasing styrene doses. The degenerative process of SGCs and spiral fibers within the osseous lamina was predominant in the middle and mid-basal turn. The electrophysiological data, obtained by recording near-field potentials from the inferior colliculus, reflected the damages of the SGCs and fibers but were not consistent with the histopathological data of the organ of Corti. Because of the weak correlation between the styrene-induced injury at the level of the organ of Corti and that induced at the level of the spiral ganglion, it is likely that two different intoxication routes exist within the cochlea. Such an assumption is discussed in the present paper.
Institut National de Recherche et de Sécurité, Laboratoire de Neurotoxicité, Avenue de Bourgogne, BP 27, Vandoeuvre 54501, France.
R
R
Lataye
P
P
Campo
C
C
Barthelemy
G
G
Loquet
P
P
Bonnet
D000818:Animals; D001299:Audiometry; D001309:Auditory Threshold / Q000187:drug effects; D003051:Cochlea / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D006198:Hair Cells, Auditory / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D008297:Male; D051381:Rats; D020318:Rats, Long-Evans; D020058:Styrene / Q000633:toxicity*
D020058:Styrene