摘要
目的通过检测耳蜗中活性氧(reactiveoxygenspecies,ROS)的含量研究褪黑素(melatonin,MLT)对噪声性聋的防护作用。方法雄性杂色豚鼠40只,随机分为4组,每组10只。第1组为正常对照组,不接触噪声,仅肌肉注射褪黑素,注射褪黑素的时间及剂量与第2组相同。第2、3、4组每天接触倍频程连续噪声(中心频率为4kHz,强度为100dBSPL)8小时,连续3天。第2组于噪声暴露前24h、即刻及噪声暴露中肌肉注射褪黑素3天。第3组在相同时间肌肉注射与第2组相同剂量的生理盐水。第4组为单纯接触噪声对照组。所有动物均于噪声暴露前及暴露后立即检测听性脑干反应(ABR)阈值,噪声暴露3天测完ABR阈值后,立即断头处死豚鼠,取出双侧耳蜗,并测定其活性氧含量。结果噪声暴露后,第2组的ABR阈移及活性氧含量分别与第3、4组比较,差异均有显著性。结论褪黑素能够减少噪声暴露后耳蜗中增多的活性氧水平,可能对噪声性耳蜗损伤具有一定的防护作用。
Objective The aim of the study was to investigate the preventive effects of melatonin(MLT) on noise -induced hearing loss by testing reactive oxygen species(ROS) levels in the cochlea. Methods 40 male pigmented guinea pigs were randomly divided into 4 groups of 10 animals each. GroupⅡwas exposed to noise and treated with melatonin. Melatonin was administered intramuscularly 24h and immediately before noise exposure and once a day until noise exposure was completed. GroupⅠwas not exposed to noise, but was treated with melatonin intramuscularly, the time of injection and the dosage were same with those of GroupⅡ. Group Ⅲ was exposed to noise and treated with normal saline intramuscularyly,the time of injection was same with that of GroupⅡ. Group Ⅳ was exposed to noise only. Group Ⅱ,Ⅲand Ⅳ were exposed to a continuous noise(4kHz, octave band, 100dB SPL) 8h/d for 3 consecutive days. All animals received ABR threshold recording immediately before and at the end of the noise exposure , then were decapitated immediately after the latest ABR threshold recording . Both the cochleae were removed and prepared for assays of ROS. Results Comparing the ABR threshold and ROS level of group Ⅱwith those of groupⅢ and Ⅳ after exposing to noise, the difference between them were all significant statistically. Conclusion Melatonin can reducet the increased ROS level in the cochlea after noise exposure, and may therefore prevent noise-induced hearing loss.
出处
《中华耳科学杂志》
CSCD
2005年第1期59-61,共3页
Chinese Journal of Otology
