Protective effect of transection of cervical sympathetic trunk on noise-induced hearing loss in guinea pigs / 实用医学杂志

ABSTRACT

Objective To investigate the protective effect of transection of cervical sympathetic trunk (TCST) on the noise-induced hearing loss (NIHL) in guinea pigs. Methods Thirty-six guinea pigs were ran-domly divided into three groups (n = 12) the operation group, the sham group and the blank control group. TCST was performed in the operation group , while the cervical sympathetic trunk in the sham group was only ex-posed and separated. The auditory brainstem response (ABR) thresholds was measured. Levels of superoxide dis-mutase (SOD) and malondialdehyde (MDA) in pasma were detected before operation (T0), before noise expo-sure (T1) and on the time of stopping noise exposure (T2), respectively. The damage situation of the outer cochlear hair cells was also checked. Results (1) At the time of T2, ABR thresholds of operation group and sham group were higher than that of the blank control group (P < 0.01), and ABR thresholds of the sham group are higher than the of the operation group (P < 0.05). (2) Levels of SOD and MDA post-noise exposure (T2) were significantly different among the three groups (P < 0.05). (3) Injured hair cells were more serious in the sham group than that in the operation group. Conclusion TCST has protective effect on NIHL in guinea pigs through increasing SOD and decreasing MDA.