Compromised potassium recycling in the cochlea contributes to conservation of endocochlear potential in a mouse model of age-related hearing loss.
The C57BL/6 strain is considered an excellent model to study age-related hearing loss (AHL). Aging C57BL/6 mice are characterized by profound hearing loss but conservation of the endocochlear potential (EP). Here we show 12-month-old C57BL/6 mice display a notable hearing loss at 4, 8, 16 and 32kHz while the EP is maintained at normal level. Morphological examination shows significant outer hair cells loss in the cochlear basal turn and atrophy of the stria vascularis (SV). Fluorescence immunohistochemical studies reveal that potassium channel KCNJ10 and KCNQ1 expression dramatically decreased in the SV. Concomitant with this, mRNA levels of KCNJ10 and KCNQ1 are also reduced. In addition, three other potassium transporters, including α1-Na,K-ATPase, α2-Na,K-ATPase and NKCC1, reduce their expression at mRNA levels as well. These observations suggest that conservation of the EP in aging C57BL/6 mice is attributable to the SV generating a new balance for potassium influx and efflux at a relatively lower level.
Department of Otolaryngology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, China; Institute of Hearing and Speech-Language Science, Sun Yat-sen University, China.
Haidi
H
Yang
Hao
H
Xiong
Qiuhong
Q
Huang
Jiaqi
J
Pang
Xuqing
X
Zheng
Lian
L
Chen
Rongjun
R
Yu
Yiqing
Y
Zheng
D000375:Aging / Q000502:physiology*; D000818:Animals; D003051:Cochlea / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D016057:Evoked Potentials, Auditory, Brain Stem; D006199:Hair Cells, Auditory, Inner / Q000473:pathology; D018072:Hair Cells, Auditory, Outer / Q000473:pathology; D034381:Hearing Loss / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D051657:KCNQ1 Potassium Channel / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009925:Organ of Corti / Q000378:metabolism / Q000473:pathology; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism; D064506:Solute Carrier Family 12, Member 2 / Q000235:genetics / Q000378:metabolism; D000098854:Kcnj10 Channel
D051657:KCNQ1 Potassium Channel; D000098854:Kcnj10 Channel; C496910:Kcnq1 protein, mouse; D024661:Potassium Channels, Inwardly Rectifying; D012333:RNA, Messenger; C578878:Slc12a2 protein, mouse; D064506:Solute Carrier Family 12, Member 2; D000254:Sodium-Potassium-Exchanging ATPase
C57BL/6; Endocochlear potential; Potassium transport; Presbycusis; Stria vascularis