Age-dependent effects of the onset of a conductive hearing loss on the volume of the cochlear nucleus subdivisions and the expression of c-fos in the mongolian gerbil (Meriones unguiculatus).
A monaural conductive hearing loss was induced by interrupting the chain of the middle ear ossicles on the right side in gerbils of four different age groups (P12-14, P20-21, P42 and P84). The volumes of the cochlear nucleus subdivisions and the number of cells that expressed immunoreactivity for c-fos after noise stimulation were determined on the left and right side in the deprived animals, and in undeprived control animals when they reached the age of 6 months. The anteroventral cochlear nucleus on the deprived side was reduced in volume when the deprivation started before the age of 3 months. The other cochlear nucleus subdivisions showed no systematic age-dependent reductions. The expression of c-fos in the dorsal cochlear nucleus appeared more resistant to a hearing loss, with deprivation being more effective in younger animals. c-fos expression was also dramatically reduced in the ventral cochlear nucleus, regardless of age at the onset of hearing loss.
Gleich
O
O
ENT Department, University of Regensburg, Germany. Otto.Gleich@klinik.uni-regensburg.de
Strutz
J
J
D000161:Acoustic Stimulation; D000375:Aging / Q000235:genetics*; D000818:Animals; D017626:Cochlear Nucleus / Q000473:pathology*; D015870:Gene Expression; D016762:Genes, fos / Q000235:genetics*; D005849:Gerbillinae; D006314:Hearing Loss, Conductive / Q000235:genetics* / Q000473:pathology*; D012683:Sensory Deprivation