Gene expression and plasticity in the rat auditory cortex after bilateral cochlear ablation.
CONCLUSIONS
The plastic changes in the auditory cortex after bilateral cochlear ablation are related to the immediate early genes as well as the neural plasticity-related genes. In addition, cross-modal plasticity may play an important role in the early changes in the auditory cortex after bilateral cochlear ablation.


OBJECTIVE
The purpose of this study was to identify candidate genes involved in the normal development of primary auditory cortex during the critical period as well as those genes specifically modulated under conditions of sensory deafferentation by bilateral cochlear ablation.


METHODS
We produced a bilaterally deaf rat model and used DNA microarray technology to analyze differential gene expression in the primary auditory cortex of bilateral cochlear ablated and sham-operated age-matched control rats. Gene expression in the auditory cortex was compared at 2, 4, and 12 weeks after surgery. For selected genes, the changes in gene expression were confirmed by real-time polymerase chain reaction (PCR).


RESULTS
In the cochlear ablation groups, the expression of immediate early genes (Egr1, 2, 3, 4, c-fos, etc.) and neural plasticity-related genes (Arc, Syngr1, Bdnf, etc.) was decreased at 2 weeks and increased at 4 weeks. The expression of neurotransmission-related genes (Gabra5, Chrnb3, Chrne, etc.) was decreased at 12 weeks.
Oh
Seung-Ha
SH
Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Seoul National University, Seoul, Korea.
Kim
Chong-Sun
CS
Song
Jae-Jun
JJ
D000818:Animals; D001303:Auditory Cortex / Q000378:metabolism*; D001306:Auditory Pathways / Q000378:metabolism; D003056:Cochlear Nerve / Q000378:metabolism*; D003423:Critical Period, Psychological; D003638:Deafness / Q000235:genetics*; D004195:Disease Models, Animal; D015870:Gene Expression / Q000502:physiology*; D017781:Genes, Immediate-Early / Q000235:genetics; D009473:Neuronal Plasticity / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012683:Sensory Deprivation / Q000502:physiology*; D009435:Synaptic Transmission / Q000235:genetics