Effects of Long Term Administration of Sodium Salicylate on the Expression of TrkB and c-fos in Rat Auditory Cortex / 听力学及言语疾病杂志

ABSTRACT

Objective To study the expression of TrkB and c-fos in rat auditory cortex after long -term ad‐ministration of sodium salicylate and the mechanisms of salicylate ototoxiclty .Methods Normal adult rats were di‐vided into three groupsnormal group without any treatment ,long -term treatment group given i .m .injections , 175 mg/kg ,twice daily at 900 am and 600 pm for consecutive 14 days and the recovered group using the same method as the chronic group except that they were sacrificed 28 days after salicylate treatment ceased .After the de‐tection of ABR ,rats were sacrificed after deep anesthesia ,and the auditory cortexes were dissected rapidly .Real-time PCR and Western-blot were explored to detect the expression of TrkB and c-fos .Results The average ABR threshold of normal rats was 36 ± 2 .23 dB SPL .The average ABR threshold of long -term group was 41 .3 ± 3 .31 dB SPL ,which was significantly increased than normal group(P0 . 05) .The expression of c-fos mRNA(1 .24 ± 0 .09)and protein(0 .70 ± 0 .12)in the long -term group were signifi‐cantly increased ,when compared with the normal group .The c-fos mRNA(1 .23 ± 0 .04)and protein(0 .68 ± 0 .08) expression in the recovered group were also significantly increased compared with the normal group .The expression of TrkB mRNA(1 .26 ± 0 .10)and protein(1 .85 ± 0 .17)in the long -term group were significantly increased ,when compared with the normal group .The TrkB mRNA(1 .23 ± 0 .07)and protein(1 .80 ± 0 .08)expression in the recov‐ered group were also significantly increased compared with the normal group .Conclusion The inereased expression of c-fos in the long -term group may be related to the enhancement of central auditory function .The inereased ex‐pression of Trk-B in the long -term group might be involved in instability of synaptic plasticity in tinnitus .