耳蜗血管纹钾钠氯化合物协同转运子对年龄相关性听力下降的影响  

Developmental expressions of Na-K-2CL co-transporter in stria vascularis of strains of C57BL/6J and Na- K-2CL co-transporter gene-knocked out mice strain associated with age-related hearing loss

作　　者：褚汉启[1] 熊浩[1] 崔永华[1] 黄孝文[1] 韩方[1] 吴振恭[1] 周良强[1] 孔维佳[1] 

机构地区：[1]华中科技大学同济医学院附属同济医院耳鼻咽喉科教研室华中科技大学同济医学院耳鼻咽喉科学研究所,武汉市430030

出　　处：《中华老年医学杂志》2007年第3期219-223,共5页Chinese Journal of Geriatrics

基　　金：国家自然科学基金资助项目（30371526）;湖北省自然科学基金资助项目（2002AB127）;教育部留学回国人员启动基金资助项目（教外司留2004-527号）

摘　　要：目的 观察具有年龄相关性听力下降（age-related hearing loss，AHL）特点的不同周龄C57BL／6J鼠和钾钠氯化合物协同联合转运子-1（Na-K-2Cl cotransporter-1，NKCC1）基因敲除鼠年龄相关性听力改变与耳蜗血管纹NKCC1表达的情况，并检测不同龄的NKCC1^＋/-杂合子小鼠耳蜗NKCC1蛋白表达及耳蜗扫描电镜形态变化，研究血管纹NKCC1在老年性聋发病中的作用。方法 应用听性脑于反应（ABR）分别检测4、8、16、32、48、60周龄组C57BL／6J小鼠和两种基因型NKCC1小鼠的听力，采用免疫组化法观察其血管纹NKCC1表达的变化，同时采用免疫印迹杂交（Western Blot）检测不同周龄小鼠耳蜗的NKCC1蛋白的含量，扫描电镜观察不同周龄小鼠的耳蜗基底膜结构。结果 C57BL／6J小鼠随鼠龄增加而出现听力下降，自16周龄时ABR阈值出现显著性增高（P〈0．05）；血管纹NKCC1蛋白表达也呈现随鼠龄增加而逐步减低，其灰度值自16周龄时显著增高（P〈0．01）。NKCC1^＋/-杂合子鼠的听力随鼠龄增长而逐渐下降，老龄小鼠的ABR阈值与其低龄时相比，阈值显著性升高（P〈0．05）。老龄小鼠的耳蜗NKCC1蛋白含量低于低龄小鼠，老龄NKCC1^＋／-小鼠的耳蜗底回外毛细胞（OHC）出现散在性点状缺失。结论 AHL小鼠血管纹NKCC1蛋白表达随年龄增长而减少，显示与AHL相关，老年性聋的发病可能与血管纹NKCC1通道蛋白的遗传特性及功能有关。Objective To investigate the dynamic age-related hearing loss and expressions of Na-K-Cl cotransporter-1 （NKCC1） in stria vascularis of strains of C57BL/6J and NKCC1 gencknocked out mice, to evaluate the relationship between NKCC1 expression in stria vascularis and agerelated hearing loss （AHL）, and the possible role of NKCC1 in the pathogenesis of presbycusis. Methods Dynamic auditory function of both C57BL/6J mice and NKCC1 mice were measured by auditory brainstem response （ABR）, dynamic expressions of NKCC1 in stria vascularis of C57BL/6J mice were detected by immunohistochemistry at 4, 8, 16, 32, 48, 60 weeks old. Morphology of cochlea was observed by electron microscope scanning and content of NKCC1 protein was detected by Western blot. Results ABR levels of C57 BL/6J mice were gradually increasing with aging. From 16 weeks old, ABR levels were significantly elevated （P〈0.05）. The dynamic expression of NKCC1 in stria vascularis of C57BL/6J mice showed age-related decrease. The density of NKCC1 in stria vascularis of C57BL/6J mice were reduced significantly also from 16 weeks old （P〈0.01）, and NKCC1^＋/-mice showed a progression of AHL as well. The mean value for ABR thresholds in response to stimulus was elevated in aged NKCC1^＋/- mice （P〈0.05）. Content of NKCC1 protein in cochlea wsa decreased with aging. The electron microscope scanning showed a kind of scattered punctiform absence of outer hair cells in elderly NKCC1^＋/- mice cochlea. Conclusions Expression of NKCC1 in stria vascularis of C57BL/6J mice is decreased with aging and may have relationship with AHL. NKCC1 of stria vascularis may play a role in the pathogenesis of AHL. Presbycusis might be correlated with the amounts of NKCC1 protein and its function.

关 键 词：耳蜗 老年性聋 钾钠氯化合物协同转运子 

分 类 号：R686[医药卫生—骨科学]