Time and frequency dependent changes of cochlear ribbon synapses in age-related hearing loss
Abstract：Objective To study possible correlations between the number of cochlear ribbon synapses and elevation of ABR thresholds related to aging. Methods C57BL/6J mice were utilized to mimic age related hearing loss in this study. ABR threshold was examined at 1M, 2M, 4M, 6M, and 12M respectively. Immunostaining combined with laser confocal mi-croscopy was used to identify RIBEYE/CtBP2, a specific pre-synaptic component of cochlear ribbon synapses, and the num-ber of labeling synaptic ribbons was calculated using the 3D max 8.0 software. Results ABR threshold elevation was first found after 4M (P<0.05), and continued to increase at 6M and 12M (P<0.05). Further, the most significant ABR threshold el-evation at a given age was identified at high frequencies (P<0.01, 8 and 16 kHz). Correspondingly, the reduction of labeling ribbon synapses was noticed along with ABR threshold shifts as the mice aged, also with more labeling synapses reduction in the high frequency regions (P<0.01, 8 and 16 kHz). However, we did not find significant loss of inner hair cells in during the same aging period. Conclusion There is faithful correlation between hearing threshold shifts and reduction of labeling synaptic ribbons, with most reduction occurring in high frequency regions. This study shows that the loss of ribbon synapses may contribute to age-related hearing loss.
Keywords：Age-related hearing lossC57 miceCochlear ribbon synapseRIBEYE/CtBP2Inner hair cell
Publication Date：2016-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 32-36 )