变压器噪声暴露对SD大鼠听力及应激状态的影响研究

目的:探究短时间内低声级强度低频的变压器噪声暴露对SD大鼠听力及应激状态方面的影响。方法:选取90只SPF级健康无听力障碍的(雌雄各半)SD大鼠作为实验对象,随机分为实验A、B组和对照C组,A、B组分别给予声级上限为65 dB SPL、60 dB SPL(频谱范围:100~800 Hz)的变压器噪声,噪声暴露时程为8周,每日噪声给予时间为22点至次日8点,C组在相同条件下饲养,不给予噪声暴露。噪声暴露结束后,通过DPOAE(畸变耳声发射)、ABR(听性脑干反应)检测、耳蜗铺片及毛细胞计数对SD大鼠听力学状况进行评估;通过血清中促肾上腺皮质激素(ACTH)、血清皮质醇(CORT)对SD大鼠的应激状态进行评估。结果:在变压器噪声暴露的8周内,各组大鼠生长状况良好,体重均呈正常生理性增长,组间无明显差异(P0.05);在变压器噪声暴露8周后,对A、B、C三组大鼠的听力学指标进行两两比较,组间均无明显差异(P0.05),对大鼠血清中促肾上腺皮质激素(ACTH)、血清皮质醇(CORT)的含量进行三组间比较,组间差异均无统计学意义(P0.05)。结论:连续暴露于声压级上限65/60 dB SPL,频谱范围为100~800 Hz的变压器噪声下8周(10小时/天)对SD大鼠听力未产生明显影响,未引发SD大鼠应激状态。

Effects of Transformer Noise on Auditory Function and Stress State in SD Rats

ABSTRACT Objective: To determine the effect of short-term transformer noise on auditory function and stress state in SD rats. Methods: 90 healthy SD rats (half male and female) with normal hearing were randomly divided into experimental group A, B and control group C. The experimental groups were exposed to the recorded transformer noise for 8 weeks (10 hours per day, 10:00 pm~8:00 am). Group A was exposed to the pressure level 65 dB SPL at Max (noise spectrum: 100-800 Hz), and group B was exposed to the pressure level 60 dB SPL at Max (noise spectrum: 100-800 Hz), control group C were maintained under the same conditions, without noise stimulation. The indexes of auditory function and stress state of SD rats were determined and compared among the three groups after an 8 weeks'' noise exposure. Results: In the 8 weeks of transformer noise exposure, the rats showed normal physiological growth, and there was no significant difference (P>0.05) among group A, B and C. After noise exposure, indices of the auditory function (distortion product otoacoustic emission, DPOAE; auditory brainstem response, ABR) and the counting and observation of cochlear hair cells of the groups were compared, and no statistically significant difference was observed (P> 0.05). In addition, there were no significant differences in the ACTH and CORT content changes among the serums of three groups (P>0.05). Conclusion: Continuous exposure to transformer noise (sound pressure level 60/65 dB SPL at Max, noise spectrum: 100~800 Hz) for 8 weeks (10 hours/day) had no significant effect on the auditory function of SD rats, and never started the stress state in rats.