Research Of GDNF Expression In The Auditory Cortex And Inferior Colliculus Of Rats With Tinnitus Induced By Sodium Salicylate

Objective: To investigate the protective effect and mechanism of Glial cell line-derived neurotrophic factor(GDNF)on auditory cortex and inferior colliculus of rats with tinnitus induced by sodium salicylate.Methods: Twenty-four rats were randomly divided into four groups according to the method of intraperitoneal injection,six for each group: the control group,acute injection group,chronic injection group and recovery group.The gap-prepulse inhibition of the acoustic startle reflex(GPIAS)was performed on the rats in each group after the above mentioned treatment,and the rats in each group were sacrificed and the auditory cortex and inferior colliculus were rapidly isolated.The expression of GDNF?RET?RAS?P-ERK in the auditory cortex and the expression of GNDF?RET?P-PI3 K p85??PAKT in the inferior colliculus were detected by Western blot.The m RNA expressions of GDNF?RET?RAS?ERK1 in the auditory cortex and the m RNA expressions of GDNF?RET?PI3K?AKT1 in the inferior colliculus were detected by fluorescence quantitative PCR(RT-q PCR).Results: 1.The GPIAS value of the SS group significantly decreased at 12 k Hz and 16 k Hz,indicating tinnitus behavior in the SS group,showing that chronic injection of sodium salicylate can cause tinnitus in rats.2.Western blot results showed that the expression levels of GDNF,RET,RAS,PERK in the auditory cortex and GDNF,RET,P-PI3 K p85??P-AKT in the inferior colliculus of the SS group were decreased compared with the NS group,AS group and RS group.The differences were statistically significant.3.Rt-q PCR results showed that the expression levels of GDNF,RET,RAS,ERK1 in the auditory cortex and GDNF,RET,PI3 K,AKT1 in the inferior colliculus of the SS group were decreased compared with the NS group,AS group and RS group.The differences were statistically significant.Conclusion: GDNF has certain protective effects on auditory cortex and inferior colliculus of tinnitus rats,and its possible mechanism may be related to GDNF-RET-RAS-ERK signaling pathway in the auditory cortex and GDNF-RET-PI3K-AKT signaling pathway in the inferior colliculus.