The ultrastructure of cochlear afferent synapse of inner hair cells in C57BL/6J mice

Objective To study the ultrastructue of afferent synapse of inner hair cells(IHCs) in C57BL/6J mice. Method The adult c57BL/6J mice with normal hearing function were selected,and the cochleas were taken out and the semi and ultra sections were performed for the ultrastructural observation by transmission electron microscope(TEM) . The ultrastructural properties within afferent synapses as well as structures nearby were analysized,and the potential correlation between the afferent synapses and other structures around was explored. Result The typical afferent synapse structure was observed including the presynaptic ribbon,synapse vesicles,the clear synapse cleft and the postsynaptic density(PSD) in mice with normal hearing ability. However,sometimes,those synaptic components could not be captured by TEM observation even in same cochlear section,but it did not mean the abnormilities of ribbon synaptic structures,and the muiltiple morphological shapes were shown in different normal ribbon synapse. Conclusion The ultrastructure of cochlear ribbon synapse in C57BL/6J mice is dynamic and the synaptic diversiform may correlate to the cochlear synaptic function in mice with normal hearing ability.