Hofstetter P, Ding D, Powers N, Salvi R J
Hearing Research Lab, SUNY at Buffalo, 14214, USA.
Hear Res. 1997 Oct;112(1-2):199-215. doi: 10.1016/s0378-5955(97)00123-8.
The outer hair cells (OHCs) are thought to be the dominant source of distortion product otoacoustic emissions (DPOAEs) in the mammalian cochlea; however, little is known about the quantitative relationship between reduction in DPOAE amplitude and the degree of inner hair cell (IHC) and OHC loss. To examine this relationship, we measured the DPOAE input/output functions in the chinchilla before and after destroying the IHCs and/or OHCs with carboplatin. Low-to-moderate doses (38-150 mg/kg, i.p.) of carboplatin selectively destroyed some or all of the IHCs along the entire length of the cochlea while sparing the OHCs. Selective loss of all the IHCs had little effect on DPOAE amplitude as long as the OHCs were present. With high doses of carboplatin (200 mg/kg, i.p.), there was complete destruction of IHCs plus massive OHC loss that decreased from the base towards the apex of the cochlea. OHC loss resulted in a large decrease in DPOAE amplitude. DPOAE amplitude at 9.6 kHz decreased at the rate of 4.1 dB for every 10% loss of OHCs. At 7.2 and 4.8 kHz, DPOAE amplitude decreased 3.1 dB and 2.4 dB per 10% OHC loss, respectively. These results indicate that OHCs are the dominant source of DPOAEs.
外毛细胞（OHCs）被认为是哺乳动物耳蜗中畸变产物耳声发射（DPOAEs）的主要来源；然而，关于DPOAE幅度降低与内毛细胞（IHCs）和OHCs损失程度之间的定量关系，人们知之甚少。为了研究这种关系，我们在用卡铂破坏IHCs和/或OHCs之前和之后，测量了灰鼠的DPOAE输入/输出函数。低至中等剂量（38 - 150 mg/kg，腹腔注射）的卡铂选择性地破坏了沿耳蜗全长的部分或全部IHCs，而OHCs未受影响。只要OHCs存在，所有IHCs的选择性损失对DPOAE幅度影响不大。高剂量卡铂（200 mg/kg，腹腔注射）会导致IHCs完全破坏以及大量OHCs损失，且从耳蜗底部向顶部损失逐渐减少。OHCs损失导致DPOAE幅度大幅下降。在9.6 kHz处，每10%的OHCs损失，DPOAE幅度下降4.1 dB。在7.2 kHz和4.8 kHz处，每10%的OHCs损失，DPOAE幅度分别下降3.1 dB和2.4 dB。这些结果表明，OHCs是DPOAEs的主要来源。
