Salicylate-induced changes of synaptic ultrastructures in the rat auditory center: a pilot study / 中国耳鼻咽喉头颈外科

ABSTRACT

OBJECTIVE To observe the changes of synaptic ultrastructures in the rat auditory center after long-term salicylate administration and to elucidate the role of neuroplasticity in some areas of the CNS and its involvement in tinnitus. METHODS The rats were divided into 4 groups the control group, the acute treatment group, the chronic treatment group, and the recovery group. We investigated ultrastructural alterations in the synapses of inferior colliculus (IC), auditory center (AC) and cerebellum (CRB) by transmission electron microscopy. RESULTS There were more synaptic vesicles (tIC=-4. 61, tAC=-7. 00, P＜0. 01), with greater postsynaptic densities(tIC=-4. 72,P＜0. 01; tAc=-3. 15, P＜0. 05), longer synaptic active zone (tIC=-4. 89, tAC=-3. 48, P＜ 0. 01), and increased synaptic interface curvature (tIC=-2. 32, tAC=-3. 17, P＜0. 05) in the chronic treatment group, as compared with the control group. There were more synaptic vesicles but no other changes in the acute salicylate-treatment group(tIC=-10. 57, tAC=-8. 34, tCRB=-9. 18,P ＜0. 01). CONCLUSION These findings showed that long-term salicylate administration have induced synaptic ultrastructural changes in the IC and AC because of neuroplasticity. These structural changes may result in increased speed and efficacy of chemical synaptic transmission. Alterations to neuroplasticity of the auditory center pathway may lead to tinnitus.