Harvard Medical School, Department of Otology and Laryngology, 25 Shattuck Street, Boston, MA 02115, USA.
J Biomed Opt. 2013 Feb;18(2):26021. doi: 10.1117/1.JBO.18.2.026021.
Hearing loss is the most common sensory deficit in the world, and most frequently it originates in the inner ear. Yet, the inner ear has been difficult to access for diagnosis because of its small size, delicate nature, complex three-dimensional anatomy, and encasement in the densest bone in the body. Evolving optical methods are promising to afford cellular diagnosis of pathologic changes in the inner ear. To appropriately interpret results from these emerging technologies, it is important to characterize optical properties of cochlear tissues. Here, we focus on that characterization using quantitative polarized light microscopy (qPLM) applied to unstained cochlear sections of the mouse, a common animal model of human hearing loss. We find that the most birefringent cochlear materials are collagen fibrils and myelin. Retardance of the otic capsule, the spiral ligament, and the basilar membrane are substantially higher than that of other cochlear structures. Retardance of the spiral ligament and the basilar membrane decrease from the cochlear base to the apex, compared with the more uniform retardance of other structures. The intricate structural details revealed by qPLM of unstained cochlear sections ex vivo strongly motivate future application of polarization-sensitive optical coherence tomography to human cochlea in vivo.
听力损失是世界上最常见的感觉缺陷，而且大多数情况下它起源于内耳。然而，由于内耳体积小、结构精细、三维解剖结构复杂以及被身体中最密集的骨头包裹，因此很难进行诊断。不断发展的光学方法有望对内耳的病理性变化进行细胞诊断。为了正确解释这些新兴技术的结果，对耳蜗组织的光学特性进行特征描述非常重要。在这里，我们使用定量偏振光显微镜 (qPLM) 对小鼠未染色的耳蜗切片进行了特征描述，小鼠是人类听力损失的常见动物模型。我们发现最双折射的耳蜗材料是胶原纤维和髓磷脂。耳囊、螺旋韧带和基底膜的延迟比其他耳蜗结构高得多。与其他结构更均匀的延迟相比，螺旋韧带和基底膜的延迟从耳蜗底部到顶部逐渐降低。未染色的耳蜗切片的 qPLM 揭示了复杂的结构细节，这强烈激发了未来将偏振敏感光相干断层扫描技术应用于体内人类耳蜗的应用。
