D-半乳糖诱导的小鼠耳蜗带状突触损伤  

Cochlear Ribbon Synapses Damage Induced by D-galactose

作　　者：杜政德 宋青玲 韩曙光[1] 柳柯[1] 龚树生[1] DU Zhengde;SONG Qingling;HAN Shuguang;LIU Ke;GONG Shusheng(Department of Otorhinolaryngology,Beijing Friendship Hospital,Capital Medical University,Beijing 100050,China;Department of Otorhinolaryngology,Hospital 731,China Aerospace Science and Industry Group,Beijing 100074,China)

机构地区：[1]首都医科大学附属北京友谊医院耳鼻咽喉科,北京100050 [2]中国航天科工集团731医院耳鼻咽喉科,北京100074

出　　处：《中华耳科学杂志》2019年第2期154-158,共5页Chinese Journal of Otology

基　　金：国家自然科学基金青年基金(81700917);中国博士后科学基金面上资助一等资助(2018M630180);深圳市科创委基础研究项目(JCYJ20160429181957912);深圳市南山区重点科技计划(2016004)~~

摘　　要：目的研究D-半乳糖诱导的衰老小鼠耳蜗带状突触数量的变化。方法 1)D-半乳糖诱导的衰老小鼠模型的构建:24只5周龄雄性C57BL/6J小鼠适应性喂养1周后随机分为2组(每组12只):①对照组:小鼠颈背部皮下注射同体积的生理盐水,每日1次,连续6周;②D-半乳糖组:小鼠颈背部皮下注射1000mg/kg D-半乳糖,每日1次,连续6周;2)ABR检测听小鼠听功能;3)免疫组织化学染色检测小鼠耳蜗线粒体DNA氧化损伤产物8-羟基-2-脱氧鸟苷(8-hydroxy-2-deoxyguanosine, 8-OHdG)的表达;4)免疫组织化学染色检测小鼠耳蜗带状突触突触前标记物CtBP2的数量;5)Western blot检测小鼠耳蜗CtBP2蛋白的表达。结果 1)D-半乳糖诱导的衰老小鼠听功能表现为ABR I波幅值的降低,而无阈值的改变;2)8-OHdG在D-半乳糖诱导的衰老小鼠耳蜗表达明显增加;3)D-半乳糖耳蜗带状突触数量明显减少;4)CtBP2蛋白在D-半乳糖诱导的衰老小鼠耳蜗表达明显减少。结论耳蜗带状突触是D-半乳糖诱导的衰老小鼠耳蜗早期出现的病变部位,D-半乳糖诱导的衰老小鼠可作为研究老年性聋耳蜗带状突触损伤的动物模型。Objective To study the change of cochlear ribbon synapses in D-galactose-induced aging mice. Methods 1) After acclimation for a week, twenty-four 5-week-old male C57BL/6J mice were randomly allocated into a control group to be injected subcutaneously with 0.9% saline once a day for 6 weeks, and a D-galactose treatment group to be injected subcutaneously with 1000 mg/kg D-galactose once a day for 6 weeks. 2) Auditory function was tested by auditory brain responses (ABRs);3) Expression of 8-hydroxy-2-deoxyguanosine (8-OHdG), a marker of mitochondrial DNA oxidative stress, was detected by immunohistochemical staining;4) Ribbon synapses were marked by CtBP2 using immunohistochemical analysis;5) CtBP2 protein expression was evaluated by western blot. Results Compared with the control group, 1) ABR wave I amplitudes were significantly decreased in the D-galactose group, with no significant change in thresholds;2) 8-OHdG expression in the cochlea was significantly increased in the D-galactose group;3) the number of ribbon synapses was significantly decreased in the D-galactose group;4) protein expression of in the cochlea was significantly decreased in the D-galactose group. Conclusion Cochlear ribbon synapses appear to be a primary insult site in D-galactose-induced aging mice, which can be an idea animal model for studying aging-associated damage of cochlear ribbon synapses.

关 键 词：老年性聋 带状突触 线粒体DNA氧化损伤 D-半乳糖 

分 类 号：R764[医药卫生—耳鼻咽喉科]