C57BL／6J小鼠听力损失与认知功能下降的相关性  

Correlation between age-related hearing loss and impairment of cognition in CS7BL/6J mice

作　　者：于亚峰[1] 翟丰[1] 戴春富[1] 胡金家[2] 

机构地区：[1]复旦大学附属眼耳鼻喉科医院耳鼻咽喉科,上海200031 [2]上海交通大学医学院解剖教研室

出　　处：《中华医学杂志》2011年第34期2430-2434,共5页National Medical Journal of China

基　　金：国家重点基础研究发展计划“973”项目（2011CB504504）;国家自然科学基金（81070785）;上海市人才发展资金（08039）

摘　　要：目的通过对老年性聋模型鼠C57BL／6J和对照组CBA／CaJ小鼠听力检测，认知行为检测以及海马CA3区突触超微结构的观察，探讨C57BIM6J小鼠年龄相关性听力损失与认知功能下降的关系。方法将C57BIM6J小鼠根据听力随年龄的变化，按年龄分为3组：6—8周、24—26周、42～44周，每组10只。CBA／CaJ小鼠按同样的年龄也分为3组，每组9只。以TDT-Ⅲ型ABR测试仪检测听力，Morris水迷宫实验检测认知行为，透射电镜观察海马突触超微结构。结果C57BL／6Jtb鼠24～26周组与4～6周组比较高频开始出现听力下降，42～44周组是3个组中听力最差的。而3组的CBA／CaJ小鼠均保持了较好的听力。42—44周组的C57BL／6J小鼠与同龄CBA／CaJ小鼠的认知行为比较，在定位航行实验中前者的潜伏期和上台前路程明显长，尤其是第3天和第4天。在空间探索实验中，42～44周组的C57BL／6J小鼠与同龄的CBA／CaJ小鼠比较穿越平台次数明显少（0．5±0．6比1．9±1．6；P〈0．05）。海马CA3区在42～44周C57BL／6J小鼠比24～26周小鼠突触间隙明显宽[（19．4±0．5）nm比（11．9±0．7）nm]，突触后致密物明显薄[（15．2±0．5）nm比（27．8±2．0）nm]，差异均有统计学意义（均P〈0．05）。而在CBA／CaJ小鼠变化不明显。结论C57BL／6J小鼠随年龄增加听力进一步下降，42～44周的C57BL／6J小鼠的听力接近全聋。同时42～4J4周C57BL／6J小鼠出现明显的认知功能下降及海马突触退变，而听力较好的同龄CBA／CaJ小鼠却没有出现相应的变化。我们推测C57BL／6J小鼠年龄相关的听力损失同其认知功能下降呈正相关。Objective To explore the correlation of age-related hearing loss and cognition impairment in C57BL/6J mice by observing hearing, cognitive function and synapses. Methods C57BL/6J and CBA/CaJ mice were divided into 3 groups. The hearing and cognitive functions of each animal was tested. And the ultrastructure of synapses was simultaneously observed for C57BL/6J mice. Results The 24- 26-week-old C57BL/6J mice developed moderate hearing loss while the 42 -44-week-old C57BL/6J counterparts suffered profound hearing loss. Whereas excellent hearing was maintained in 3 groups of CBA/ CaJ mice within 44 weeks. During cognitive test, the performance of 42 -44-week-old C57BL/6J mice was significantly worse than CBA/CaJ mice. During probe test, the number of platform crossing of 42 - 44-weekold C57BL/6J mice was smaller than that of CBA/CaJ mice （0.5 ± 0.6 vs 1.9 ± 1.6 ; P 〈 0.05 ）. The 42 -44-week-old C57BL/6J mice had a wider synaptic cleft and a thinner postsynaptic density than the 24 - 26-week-old C57BL/6J counterparts [ synaptic cleft： （ 19.4± 0.5 ） nm vs （ 11.9± 0.7 ） nm; postsynaptic density：（15.2 ±0.5） nm vs （27.8 ±2.0） nm; both P 〈0. 05]. Furthermore, the degeneration of synapses in hippocampus CA3 area of C57BL/6J mice were clearly observed at 42 -44 weeks of age, but not seen in CBA/CaJ mice. Conclusion Age-related hearing loss might impact on the cognition impairment in C57 BL/6J mice.

关 键 词：老年性聋 海马 突触 

分 类 号：R764[医药卫生—耳鼻咽喉科]