摘要
目的 了解庆大霉素 (gentamicin ,GM)对豚鼠血管纹黑色素的影响及其作用机制。方法 豚鼠杂色 40只和白色 2 0只每日肌内注射庆大霉素 15 0mg/kg体重 7d后用脑干诱发电位仪检测两种豚鼠的听阈变化 ,以透射电镜观察杂色豚鼠用药前后血管纹内黑色素含量及酪氨酸酶活性的变化 ,并用免疫组化法观察血管纹增殖细胞核抗原 (proliferatingcellnuclearantigen ,PCNA)表达的变化。结果庆大霉素作用后 ,杂色和白色豚鼠的听阈与用药前比较 ,差异有非常显著性意义 (P <0 0 0 1) ,且两组豚鼠间的阈移差异也有非常显著性意义 (P <0 0 0 1)。杂色豚鼠对照组和实验组 (各 10只 )血管纹中间细胞内平均 ( x±s,以下同 )每个观测区域 (30 0 μm2 )的黑素体含量分别为 (19 83± 2 74)个和 (5 8 33± 16 2 2 )个 ,差异有非常显著性意义 (P <0 0 0 1) ;酪氨酸酶活性反应产物面积与测定区域面积之比从1 6 5 %± 0 40 %增加为 3 45 %± 0 41% ,差异有非常显著性意义 (P <0 0 0 1) ;但对照组与实验组PCNA阳性中间细胞分别为 (14 0 8± 2 76 )个和 (13 5 8± 2 0 9)个 ,差异无显著性意义 (P >0 0 5 )。结论 庆大霉素作用后血管纹内黑色素含量的增加 ,可能是由于药物促进了酪氨酸酶活性的增强 。
Objective To investigate the effect and its mechanism of gentamicin(GM) on melanin in stria vascularis of guinea pig. Methods The differences of auditory thresholds between pigmented and albino guinea pigs, given GM of 150 mg/kg for 7 days, were studied. Moreover,the content of melanosomes,activity of tyrosinase and expression of proliferating cell nuclear antigen(PCNA) in intermediate cells of stria vascularis in gentamicin-treated pigmented guinea pigs were compared with those in control animals by electron microscope and immunohistochemistry,respectively. Results After gentamicin exposure,the auditory thresholds of all animals increased significantly (P<0.001),whereas threshold shifts averaged across all frequencies of pigmented animals were much less than those of the albinos(P<0.001). The number of melanosomes of each examined area(300μm 2) in intermediate cells was obviously increased from 19.83±2.74 to 58.33±16.22.The ratio of tyrosinase reaction products area to the total measured area was significantly increased from 1.65%±0.40% to 3.45%±0.41% after gentamicin exposure. However,the numbers of positive intermediate cells expressing PCNA were 14.08±2.76 and 13.58±2.09 before and after gentamicin treatment, respectively. But there was no statistically significant difference between them (P>0.05). Conclusion The increase of content of melanin in stria vascularis after GM exposure does not result from the change of proliferating activity of melanocytes,but from the enhanced tyrosinase activity. Melanins in stria vascularis may possess the ability to protect the inner ear from ototoxicity of gentamicin.
出处
《中华耳鼻咽喉科杂志》
CSCD
北大核心
2002年第5期324-328,共5页
Chinese Journal of Otorhinolaryngology
关键词
黑色素小体
一元酚单氧酶
庆大霉素类
增殖细胞核抗原
血管纹
Melanosomes
Monophenol monooxygenase
Gentamicins
Proliferating cell nuclear antigen
Stria vascularis
