Pan Dorothy W, Yang Zihan, Kim Wihan, Biju Kevin, Gnedeva Ksenia, Applegate Brian E, Oghalai John S
Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA.
Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA.
Hear Res. 2025 Jul 29;466:109380. doi: 10.1016/j.heares.2025.109380.
Optical Coherence Tomography (OCT) has been used to characterize cochlear endolymphatic hydrops (ELH) with distention of Reissner's membrane in mice after noise exposure. Noise exposure has been correlated with vestibular dysfunction, so we hypothesized that noise exposure can lead to ELH in the vestibular system. Little work has been performed using OCT to image the membranous labyrinth in the lateral and posterior semicircular canals (SCCs). We show that OCT with 12.5 µm axial resolution and 13.2 µm lateral resolution can image the SCCs and delineate the membranous labyrinth in anesthetized mice. A high-resolution OCT system with 2.45 µm axial and 3.95 µm lateral resolution provides improved distinction between the endolymphatic and perilymphatic fluid spaces that enables quantification of the endolymph to perilymph (E/P) area ratio in the SCCs. The LSCC E/P ratio in noise exposed mice (5.16 ± 0.67, mean ± standard deviation, n = 12) is significantly increased (p = 0.0014, unpaired Student's t-test) compared to control mice (4.26 ± 0.41, n = 10). Similarly, the PSCC E/P ratio in noise exposed mice (4.92 ± 0.52, n = 12) is significantly increased (p = 3.65e-6, unpaired Student's t-test) compared to control mice (4.00 ± 0.37, n = 11). Furthermore, the PSCC and LSCC E/P ratios correlate significantly (R = 0.284, p = 0.0063, linear regression). These data demonstrate that noise exposure leads to increased E/P ratio, a measurement of ELH, in both the LSCC and PSCC in mice, and this corresponds to ELH present in the cochlea after noise exposure. Therefore, noise exposure leads to ELH in both the cochlea and the vestibular system, suggesting a pathway for noise exposure to cause vestibular dysfunction.
光学相干断层扫描（OCT）已被用于在噪声暴露后对小鼠中伴有内耳膜迷路积水（ELH）及Reissner膜扩张的耳蜗进行特征描述。噪声暴露与前庭功能障碍相关，因此我们推测噪声暴露可导致前庭系统出现ELH。利用OCT对水平和后半规管（SCC）中的膜迷路进行成像的研究工作较少。我们发现，轴向分辨率为12.5 µm、横向分辨率为13.2 µm的OCT能够对麻醉小鼠的SCC进行成像并勾勒出膜迷路。轴向分辨率为2.45 µm、横向分辨率为3.95 µm的高分辨率OCT系统能更好地区分内淋巴和外淋巴液腔，从而能够量化SCC中的内淋巴与外淋巴（E/P）面积比。与对照小鼠（4.26±0.41，n = 10）相比，噪声暴露小鼠的水平半规管E/P比（5.16±0.67，平均值±标准差，n = 12）显著升高（p = 0.0014，非配对学生t检验）。同样，与对照小鼠（4.00±0.37，n = 11）相比，噪声暴露小鼠的后半规管E/P比（4.92±0.52，n = 12）显著升高（p = 3.65×10⁻⁶，非配对学生t检验）。此外，后半规管和水平半规管的E/P比显著相关（R = 0.284，p = 0.0063，线性回归）。这些数据表明，噪声暴露会导致小鼠水平半规管和后半规管中的E/P比升高，这是ELH的一种测量指标，且这与噪声暴露后耳蜗中出现的ELH相对应。因此，噪声暴露会导致耳蜗和前庭系统均出现ELH，提示了噪声暴露导致前庭功能障碍的一条途径。
