RESUMO
Objective To study the expression of Nuclear factor E2 related factor 2 (Nrf2) ,Superoxide Dis‐mutas 1 (SOD1) ,and Heme Oxygenase- 1( HO -1) factors related to Nrf2 signaling pathway in noise-induced cochlear injury of rats .Methods A total of 30 SD rats were randomly and equally assigned into the following 2 groups :noise group and normal control group .The rats in noise group were exposed to an 115 dB SPL continuous steady white noise for 12 hours ,then 1 day ,3 days ,and 7 days later ,the rats receveid the ABR and DPOAE testing after noise exposure .Both RT -PCR and Peggy Sue trace protein detection techniques were used to detect gene ex‐pression in Nrf2 /Keapl-ARE signaling pathway and the protein levels by cochlear tissue sampling after noise ex‐posure 7 days later .Results The ABR thresholds in the noise group was higher than those of in normal control group after noise exposure 1 ,3 ,and 7 days later (P<0 .05) .The DPOAE values of noise group were significantly lower than those of normal control group (P<0 .05) .The up -regulation of expression of Nrf2 ,SOD1 ,HO -1 mRNA(1 .11 ± 0 .05 ,1 .45 ± 0 .12 ,1 .15 ± 0 .03) in noise group were higher than those of in the normal control group after noise exposure 7 days later (1 .00 ± 0 .02 ,1 .10 ± 0 .12 ,0 .92 ± 0 .08) ,and the differences were statistically sig‐nificant (P<0 .05) .And in Peggy Sue trace detection system ,we also found SOD1 ,HO -1 protein levels in noise group were higher than those of in normal control group .Conclusion After the noise -induced cochlear injury in rat ,Nrf2 expression in the cochlea increased and up-regulatd expression of downstream gene and protein content such as antioxidant enzymes SOD1 and HO-1gene by regulating Nrf2 /Keapl-ARE signaling pathway ,which may be involved in protection against oxidative stress injury in noise-induced cochlear injury of rat .