Downregulation of Inwardly Rectifying Potassium Channel 5.1 Expression in C57BL/6J Cochlear Lateral Wall

Age-related hearing loss(AHL) is one of the most common sensory disorders among elderly persons. The inwardly rectifying potassium channel 5.1(Kir5.1) plays a vital role in regulating cochlear K~+ circulation which is necessary for normal hearing. The distribution of Kir5.1 in C57BL/6J mice cochleae, and the relationship between the expression of Kir5.1 and the etiology of AHL were investigated. Forty C57BL/6J mice were randomly divided into four groups at 4, 12, 24 and 52 weeks of age respectively. The location of Kir5.1 was detected by immunofluorescence technique. The m RNA and protein expression of Kir5.1 was evaluated in mice cochleae using real-time polymerase-chain reactions(RT-PCR) and Western blotting respectively. Kir5.1 was detected in the type Ⅱ and Ⅳfibrocytes of the spiral ligament in the cochlear lateral wall of C57BL/6J mice. The expression levels of Kir5.1 m RNA and protein in the cochleae of aging C57BL/6J mice were down-regulated. It was suggested that the age-related decreased expression of Kir5.1 in the lateral wall of C57BL/6J mice was associated with hearing loss. Our results indicated that Kir5.1 may play an important role in the pathogenesis of AHL.