The Expression of EphA4 in Inferior Colliculus Involves in the Pathology of Salicylate Induced Tinnitus in Rat / 听力学及言语疾病杂志

ABSTRACT

Objective To investigate the influences of sodium salicylate on the auditory brainstem response (ABR)and expression of EphA4mRNA in rat inferior colliculus and its effects on salicylate ototoxicity.Methods A total of 30 healthy SPF rats were randomly divided into five groupsthe control group (without any treatment),S7 (i.m.injection of sodium salicylate,175mg/kg,twice daily for 7 days),S14(the same method as S7,twice daily for 14 days),S14+R14(the same method as S14,twice daily for 14 days and recovered for 14 days),and S14+R28(the same method as S14,twice daily for 14 days and recovered for 28 days).After the ABR assessment,rats were sacri-ficed after deep anesthesia and the inferior colliculus tissues were dissected.Real-time PCR was used to detect the expression of EphA4mRNA.Results Compared with the control group,ABR thresholds in the S7 group and S14 group were increased significantly (P0.05).The inferior colliculus EphA4mRNA expression level of S7 group was signifi-cantly decreased than the control group (P0.05).Conclusion Long term injection of sodium salicylate can cause changes in the inferior colliculus of EphA4mRNA which are related closely with synaptic plasticity.It may lead the alteration of the inferior colliculus synaptic plasticity,which is associated with the changes of the hearing failure and the tinni-tus behavior.This indicates that EphA4 which is considered as a related protein in the inferior colliculus may play an important role in the pathology of tinnitus.