Harding G W, Baggot P J, Bohne B A
Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri 63110.
Hear Res. 1992 Nov;63(1-2):26-36. doi: 10.1016/0378-5955(92)90070-4.
To determine whether or not exposure to noise causes an alteration in the height of the organ of Corti (OC), 16 cochleas which had been exposed for one or two hours to an octave band of noise with a center frequency of 4 kHz and a sound pressure level of 108 dB were examined microscopically as whole mounts. These specimens were divided into four groups: early ears (N = 3) recovered less than 0.6 hours following the exposure; intermediate ears (N = 5) recovered 0.6-4.0 hours; 1-day ears (N = 3) recovered 24 hours; and late ears (N = 5) recovered 2-21 days. Height was measured at three positions across the OC and at multiple percentage locations from apex to base. The OC-height data from the noise-exposed cochleas were compared statistically to those from ten control cochleas. A significant reduction (P < or = 0.01) in OC height at the third outer hair cell (OHC) was first evident in the early ears in the region 65-95% distance from the apex. The height was reduced even further in the intermediate ears and included a region from 15-25% distance from the apex as well as the 65-95% region. In the late ears, heights had returned to control values, except within focal OC lesions. Height at the first row of OHCs was less affected than at the third row, and height at the inner hair cell (IHC) was least affected. These height changes were accompanied by distortion of the shape and position of OHCs, the shape of Deiters' cells and buckling of inner and outer pillar bodies. Sometimes IHCs had distorted shapes and were displaced from their usual positions. Although no functional measures were obtained from these ears, data from the literature indicate that the exposure described above would have produced a sizable threshold shift. Transient reduction in OC height likely accounts for some portion of noise-induced threshold shifts.
为了确定暴露于噪声是否会导致柯蒂氏器（OC）高度发生改变，对16个耳蜗进行了显微镜下的整体标本检查，这些耳蜗已暴露于中心频率为4 kHz、声压级为108 dB的倍频程噪声中1或2小时。这些标本分为四组：早期耳朵（N = 3），暴露后恢复时间少于0.6小时；中期耳朵（N = 5），恢复时间为0.6 - 4.0小时；1天耳朵（N = 3），恢复时间为24小时；晚期耳朵（N = 5），恢复时间为2 - 21天。在OC的三个位置以及从蜗顶到蜗底的多个百分比位置测量高度。将噪声暴露耳蜗的OC高度数据与十个对照耳蜗的数据进行统计学比较。在早期耳朵中，距蜗顶65 - 95%区域的第三排外毛细胞（OHC）处的OC高度首先出现显著降低（P≤0.01）。在中期耳朵中，高度进一步降低，包括距蜗顶15 - 25%区域以及65 - 95%区域。在晚期耳朵中，除了局部OC病变区域外，高度已恢复到对照值。第一排OHC的高度受影响小于第三排，内毛细胞（IHC）的高度受影响最小。这些高度变化伴随着OHC的形状和位置扭曲、Dieters细胞的形状以及内、外柱体的弯曲。有时IHC的形状会扭曲并从其正常位置移位。尽管未从这些耳朵获得功能测量数据，但文献数据表明上述暴露会产生相当大的阈值偏移。OC高度的短暂降低可能是噪声诱导阈值偏移的部分原因。
