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目的观察高强度脉冲噪声暴露后豚鼠听功能及耳蜗结构的变化,探讨用于毛细胞再生研究的噪声性聋动物模型的建立方法。方法健康成年白色红目豚鼠50只,雌雄不限,体重250～300g。随机分成2组,正常对照组10只,噪声暴露组40只。给予脉冲噪声(压力峰值为175.0dB SPL,脉宽0.25ms,间隔时间20秒)连续暴露200次。于噪声暴露前及暴露后1周、4周、8周检测听性脑干反应(auditory brainstem respons,ABR),毛细胞计数及耳蜗铺片免疫组化观察耳蜗结构变化。结果高强度脉冲噪声暴露后1周,40只豚鼠中有21只(52.5%)双耳各频率ABR阈值≥95dB SPL。继续观察至噪声暴露后4周及8周,ABR阈值没有恢复,1周、4周、8周各频率ABR阈值比较无统计学差异(P>0.05)。毛细胞计数结果显示,噪声暴露致极重度聋后1周,内毛细胞平均缺失率为91.4%,外毛细胞平均缺失率为97.2%。免疫组化染色分析结果显示,噪声暴露致聋后1周,内、外毛细胞胞核大部分缺失,内毛细胞内侧及外毛细胞外侧的支持细胞的胞核存在。结论高强度脉冲噪声暴露可造成豚鼠极重度感音神经性聋,耳蜗毛细胞广泛缺失且无法自行恢复,而支持细胞大部分存留,是进行毛细胞再生研究的理想动物模型。
Objective To observe the changes of auditory function and cochlear structure of guinea pig exposed to high intensity impulsive noise and to establish a method for establishing animal model of noise-deafness for hair cell regeneration. Methods Healthy adult white red guinea pigs 50, male or female, weight 250 ~ 300g. Randomly divided into two groups, 10 normal control group, noise exposure group 40. Impulse noise (peak pressure 175.0 dB SPL, pulse width 0.25 ms, interval 20 seconds) was continuously exposed 200 times. Auditory brainstem respons (ABR), hair cell count and cochlear implants were used to observe the change of cochlear structure before noise exposure and at 1 week, 4 weeks and 8 weeks after exposure. Results One week after exposure to high intensity impulsive noise, 21 of 50 guinea pigs (52.5%) had ABR threshold ≥95 dB SPL. ABR threshold did not recover until 4 and 8 weeks after noise exposure. There was no significant difference in ABR threshold between 1, 4 and 8 weeks (P> 0.05). Hair cell count results showed that the noise exposure was extremely severe 1 week after deafness, the average loss of internal hair cells was 91.4%, the average loss of outer hair cells was 97.2%. The results of immunohistochemical staining showed that most of the nuclei of inner and outer hair cells were absent at 1 week after deafness exposure, and the nuclei of supporting cells outside of inner hair cells and outer hair cells existed. Conclusion Exposure to high intensity impulsive noise can cause extremely severe sensorineural deafness in guinea pigs. Cochlear hair cells are extensively devoid and can not recover spontaneously, while most of the supporting cells remain. It is an ideal animal model for hair cell regeneration research.