Akademik Veri Yönetim Sistemi
Journal of International Advanced Otology, cilt.8, sa.2, ss.187-195, 2012 (SCI-Expanded)
Objective: To investigate Brain-derived neurotrophic factor (BDNF) and glutamate decarboxylase (GAD) 65 expressions of rat primary auditory cortex (PAC) and inferior colliculus (IC) in response to noise and cochlear ablation. Materials and Methods: Of 20, 4 rats were assigned to control group. The remaining 16 rats were divided into noise and ablation groups. Each group was further stratified equally based on timing of sacrifice, 2 nd hour and 28 th day. The rats underwent stereotaxic surgery in order to obtain tissue samples from PAC and IC. Expression rates of BDNF exon IV and GAD 65 genes were measured using Relative Quantification with Real Time Polymerase Chain Reaction. Results: PCR showed that in noise group there was a reduction in GAD 65 of PAC bilaterally and an elevation in GAD 65 expression of IC contralaterally at 2 nd hour. BDNF expression of PAC showed ipsilateral and contralateral elevations on the 28 th day. Ipsilateral BDNF elevation in IC was observed at 2 nd hour. Significant elevation of GAD 65 expression of PAC was detected bilaterally on 28 th day compared to 2 nd hour levels while there was no change in BDNF in PAC and IC bilaterally. In ablation group, bilateral expressions of GAD 65 in IC showed an elevation at 2 nd hour. GAD 65 expression in PAC was low bilaterally on 28 th day. There was no significant change in BDNF levels in PAC bilaterally in both periods. There was an elevation only in contralateral IC expression of GAD 65 on 28 th day compared to 2 nd hour. Conclusion: Clear differences were detected in GAD 65 expression of PAC and IC in response to permanent and temporary hearing loss. GAD 65 expression in PAC is almost exactly opposite to GAD 65 expression in IC. Whereas GAD 65 expression in PAC appears to be linked to presence of hearing loss, its expression in IC might be linked to existence of excessive stimuli and permanency of hearing loss. This is also likely to be related to protective action of IC. Ablation did not cause BDNF exon IV expression. The results showed slow reaction of BDNF in PAC in response to acoustic trauma. © 2005 The Mediterranean Society of Otology and Audiology.