Popelar Jiri, Groh Daniel, Pelánová Jana, Canlon Barbara, Syka Josef
Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
Neurobiol Aging. 2006 Mar;27(3):490-500. doi: 10.1016/j.neurobiolaging.2005.03.001. Epub 2005 Apr 7.
Auditory function in Fischer 344 (F344) and Long Evans (LE) rats was monitored during their lifespan by evaluating hair cell loss, middle-ear compliance and the recording of otoacoustic emissions and auditory brainstem responses. The results revealed a faster deterioration of hearing function in F344 rats compared with LE rats, resulting in larger hearing threshold shifts, a decrease in the latency and amplitude of click-evoked auditory brainstem responses, diminution of the distortion product otoacoustic emissions and a decrease in middle-ear compliance. However, hair cell loss, observed only at the most basal and apical parts of the organ of Corti, was comparable in older individuals of both rat strains. The results suggest involvement of cochlear (stria vascularis) and extracochlear (middle-ear) pathological changes during ageing. Thus, F344 rats represent a complex mix of conductive hearing loss (with low-frequency threshold shift, declining parameters of the middle-ear admittance and asymmetric otoacoustic emissions) and sensorineural hearing loss (with a decrease in the amplitudes of auditory brainstem response and a high-frequency threshold shift).
在Fischer 344（F344）大鼠和Long Evans（LE）大鼠的整个生命周期中，通过评估毛细胞损失、中耳顺应性以及记录耳声发射和听觉脑干反应来监测其听觉功能。结果显示，与LE大鼠相比，F344大鼠的听力功能衰退更快，导致听力阈值变化更大、短声诱发的听觉脑干反应的潜伏期和振幅降低、畸变产物耳声发射减弱以及中耳顺应性下降。然而，仅在柯蒂氏器最基部和顶部观察到的毛细胞损失，在两种大鼠品系的老年个体中相当。结果表明，衰老过程中涉及耳蜗（血管纹）和耳蜗外（中耳）的病理变化。因此，F344大鼠代表了传导性听力损失（伴有低频阈值变化、中耳导纳参数下降和不对称耳声发射）和感音神经性听力损失（伴有听觉脑干反应振幅降低和高频阈值变化）的复杂组合。
