快速老化小鼠听功能及耳蜗组织神经生长因子受体p75的增龄性变化

Degenerative Changes of Auditory Function and Age-Related Expression of NGFR p75 in the Cochlea of the Senescence Accelerated Mouse

目的探讨快速老化小鼠的听功能及耳蜗组织神经生长因子受体p75(nerve growth factor receptor p75,NGFR p75)表达的增龄性变化特点。方法对3、5、7月龄的快速老化小鼠亚系8(SAMP8小鼠)行8kHz短纯音听性脑干反应(ABR)检测,并用免疫组化染色方法检测耳蜗组织NGFR p75的表达,观察随月龄的增长其ABR反应阈和NGFR p75的表达变化。结果 SAMP8小鼠ABR反应阈值随着月龄增加而显著增高(P<0.05);NGFR p75在不同月龄SAMP8小鼠耳蜗螺旋神经节和毛细胞中均有表达,其光密度值随着月龄增加而显著增高(P<0.05)。结论快速老化小鼠NGFR p75的表达水平随着听觉功能的年龄相关性减退而增高,说明NGFR p75可能与耳蜗功能增龄性退化有关。

Objective To determine degenerative changes of auditory function and age--related expression of nerve growth factor receptor p75（NGFR p75） in the cochlea of the senescence accelerated mouse. Methods The 8 kHz tone burst auditory thresholds and age--related expression of NGFR p75 in the cochlea were studied in the se- nescence accelerated mouse/prone 8（SAMP8） at 3,5,7 months. The expression of NGFR p75 was analyzed by the optical density of immunohistochemical staining. Results For the auditory function evaluation,the SAMP8 devel- oped a progressive hearing loss at 8 kHz showing an age--related significant increase（P〈0.05）. The expression of NGFR p75 in the cochlea showed that there was NGFR p75 expressed in the cochlea of the SAMP8 throughout the development with an age--related significant increase（P〈0.05）. Conclusion The expression level of NGFR p75 increase when the SAMP8 develops a progressive hearing loss. This indicates that NGFR p75 probably is possibly re- lated with functional degradation of the cochlea.