镁对大鼠噪声性听力损失的防护作用

Preventive effects of Magnesium on noise-induced hearing loss in rats

关键词:  噪声性聋  镁  大鼠

Key words:  noise-induced hearing loss  Magnesium  rat

摘要:

目的　 观察镁对大鼠噪声性听力损失的防护作用。方法　 雄性SD大鼠24只随机分成3组，分别为低镁组100 mg /kg,适量镁组507 mg /kg及高镁组1 000 mg /kg，采用对喂法(pair-fed)喂养镁含量不同的人工半合成饲料，20 d后将大鼠暴露于强度为105 dB SPL，中心频率为4 kHz的倍频程噪声3 h后，检查其听性脑干反应(auditory brainstem response,ABR)和畸变产物耳声发射(distortion product otoacoustic emissions，DPOAE)。结果　ABR阈移低镁组为14.2±1.7，适量镁组为24.3±3.1，高镁组为4.6±1.7，3组间阈移值差异有显著性意义（P<0.05），3组DPOAE在噪声暴露前后幅值改变分别为低镁组19.0±3.8～20.0±4.5 dB，适量镁组12.0±3.0～14.5±3.5 dB，高镁组3.5±0.8～4.0±1.0 dB，3组间幅值改变差异有显著性意义（P<0.05）。结论　 适量镁能降低大鼠对噪声暴露后的敏感性，对噪声性听力损失有防护作用。

Abstract:

Objective 　To investigate the preventive effects of magnesium on noise-induced hearing loss in rats. 　Methods　Twenty-four Sprague Dawley male rats were divided into three groups, 8 each and fed with man-made dietary .The rates in the first group were fed Mg deficient diet (100 Mg mg/kg diet), in the second group were fed Mg adequate diet (507 Mg mg/kg diet), while in the third group fed Mg excess diet (1000 Mg mg/kg diet). After 20 days adaptation to pair－fed, a acoustic trauma experiment was carried on. All rats were exposed to octave band noise with a central frequency of 4 kHz, 105 dB SPL, for 3 h. Auditory brainstem response (ABR), distortion product otoacoustic emissions (DPOAE) was recorded. 　Results　Comparing the ABR threshold, the change of DPOAE of the third group with those of the first group and the second group after exposing to noise, the difference between them were all significant statistically. 　Conclusion　Mg deficiency could increase the susceptibility of rats to noise damage.