摘要
目的探讨快速老化小鼠听觉功能和耳蜗螺旋神经元的增龄性变化。方法选取1、3、5、7、9月龄的快速老化小鼠亚系1(Senescence accelerated mouse/prone 1,SAMP 1)作为实验组,而同龄抗快速老化小鼠亚系1(Senescenceaccelerated mouse/resistance 1,SAMR 1)作为SAMP 1的正常对照组。分别观察其8 kHz短纯音听觉脑干反应阈值、耳蜗螺旋神经节细胞透射电镜形态学、末端脱氧核苷酸转移酶介导的dUTP原位切口末端标记[terminal deoxynucle-otidyl transferase(TdT)dUTP nick end labeling]TUNEL免疫组化染色等方面的增龄性变化。结果①听功能检测。第7、9个月龄SAMP 1小鼠跟同龄SAMR 1小鼠比较听觉脑干反应阈值差异有统计学意义;②耳蜗螺旋神经节细胞形态学检测。第79、个月龄SAMP 1小鼠可见螺旋神经元凋亡,而同龄SAMR 1小鼠罕见螺旋神经元凋亡;③耳蜗中轴位切片TUNEL染色。第7个月龄SAMR 1小鼠SGN细胞核基本上不着色[TUNEL染色阳性率为(2.27±2.43)%],第7个月龄SAMP 1小鼠部分SGN胞核着色[染色阳性率为(11.36±4.96)%],两者的染色阳性率差异有统计学意义。结论SAMP 1小鼠随月龄增长耳蜗螺旋神经元凋亡、听功能减退,7月龄SAMP 1小鼠即出现明显的听功能老化特征,可作为老年聋动物模型用于耳聋的相关研究。
Objective To detennine age-related spiral ganglion neuron damages and hearing loss in the senescence accelerated mice. Methods The auditory thresholds and the morphological changes of the spiral ganglion neurons were studied in senescence accelerated mouse/prone 1 （SAMP 1 ） mice of 1, 3, 5, 7 and 9 months. Normal aging senescence accelerated mouse/resistance 1 （SAMR 1） mice served as the control group. 8 kHz threshold of auditory brain-stem response was determined, transmission electron microscopy and tenninal deoxynucleotidyl transferase（TdT） dUTP nick end labeling（TUNEL） were used to observe the auditory function changes, the morphological changes and the immunohistochemical changes. Results Auditory function Corn - pared with the SAMR 1 mice, SAMP 1 mice of 7 or 9 months developed a progressive heating loss at 8kHz, which showed an agerelated significant increase（ P 〈 0.05）. Morphological observation： The SAMR 1 mice had no apoptosis in the spiral ganglion neurons （SGNs）, while the SAMP 1 mice of 7 or 9 months developed a significant apoptosis in the SGNs. TUNEL observation： Negative reaction for TUNEL staining was found in the SGNs in the SAMR 1 mice of 7 months, and a positive reaction was found in the nucleolus of the part of the SGNs of the SAMP 1 mice of 7 months. The image analysis showed that the percentage of positive SGNs of the SAMP 1 mice of 7 months was significantly higher than that of the SAMR 1 mice of 7 months. Conclusions SAMP 1 mice can be used for investigating mechanism of auditory-function-aging and as a pertinent animal model of presbyacousis.
出处
《山东大学耳鼻喉眼学报》
CAS
2008年第3期215-217,221,共4页
Journal of Otolaryngology and Ophthalmology of Shandong University
基金
教育部春晖计划科研项目(Z2005-2-45002)
广西卫生厅科研项目(重200746和Z2007193)
关键词
快速老化小鼠
听觉脑干反应阈值
螺旋神经元
凋亡
Senescence accelerated mouse
Threshold of the auditory brain stem response
Spiral ganglion neuron
Apoptosis
