稳态强噪声暴露后听神经动作电位及神经丝蛋白表达的观察

Effect of Intensive Continual Noise Exposure on Compound Action Potential and Neurofilament Protein Expression in Guinea Pigs

目的 观察豚鼠暴露于稳态强噪声后听神经复合动作电位 (CAP)及神经丝蛋白 (NFP)的变化。方法 选用 2 0只 ( 4 0耳 )Preyer反射正常的健康豚鼠 ,分为 4组 ,噪声暴露后存活 7天组 (N - 7d)、14天组 (N - 14d)和 2个月组 (N - 2m)各 5只 ,空白对照组 (C) 5只。噪声强度 130dB(A)SPL ,连续暴露 5小时 ,于暴露前、暴露后 3、7、14天、暴露后 2个月分别测试CAP -N1波反应阈。免疫组化反应分别检测对照组、暴露后 7、14天组、暴露后 2个月组动物耳蜗内NFP的表达。结果 稳态强噪声暴露后CAP -N1波反应阈明显增高 ,于暴露后 7天基本稳定。暴露后7、14天NFP表达无明显变化 ,暴露后 2月NFP表达显著减弱。结论 130dB(A)SPL稳态强噪声暴露 5小时可以导致豚鼠CAP中重度永久性阈移 ,噪声损伤的早期NFP改变不明显 ,耳蜗NFP染色反应随着存活时间延长逐渐减弱 。

Objective To observe the changes of compound action potential and neurofilament protein after intensive continual noise exposure in guinea pigs.Methods Twenty healthy guinea pigs with normal Preyer′s reflex were divided into four groups, five animals were exposed to noise and survived seven days(N-7d), five animals were exposed to noise and survived fourteen days(N-14d), five were exposed and survived two months(N-2m), the other five served as non-exposure control group(C). The intensity of the noise was 130 dB(A) SPL ,and the exposure was five hours continuously. The threshold of CAP-N1 was recorded pre-exposure,three days ?seven days ? fourteen days and two months after exposure respectively. The neurofilament proteins of the cochlear nerve were detected in N-7 d?N-14 d?N-2 m and C groups.Results The increased threshold of CAP-N1 was seen after exposure and the threshold shift was stable at seven days after exposure. The NFP expression showed no significant difference fourteen days after exposure. Two months after exposure, the immunohistochemistry reactivity clearly decreased.Conclusion Middle to severe permanent threshold shift was produced by five hours exposure of 130 dBSPL stable noise. In the early-stage after noise exposure,the NFP expression had no significant difference in contrast to normal animals. The NFP staining decreased while the survive time increased, which indicating the skeleton protein degeneration of neural fibers after noise trauma.