Hirose Keiko, Rutherford Mark A, Warchol Mark E
Department of Otolaryngology, Washington University, 660 S. Euclid Avenue, Campus Box 8115, St. Louis, MO 63110, United States.
Department of Otolaryngology, Washington University, 660 S. Euclid Avenue, Campus Box 8115, St. Louis, MO 63110, United States.
Hear Res. 2017 Sep;352:70-81. doi: 10.1016/j.heares.2017.04.006. Epub 2017 Apr 28.
The cochlea and the vestibular organs are populated by resident macrophages, but their role in inner ear maintenance and pathology is not entirely clear. Resident macrophages in other organs are responsible for phagocytosis of injured or infected cells, and it is likely that macrophages in the inner ear serve a similar role. Hair cell injury causes macrophages to accumulate within proximity of damaged regions of the inner ear, either by exiting the vasculature and entering the labyrinth or by the resident macrophages reorganizing themselves through local movement to the areas of injury. Direct evidence for macrophage engulfment of apoptotic hair cells has been observed in several conditions. Here, we review evidence for phagocytosis of damaged hair cells in the sensory epithelium by tissue macrophages in the published literature and in some new experiments that are presented here as original work. Several studies also suggest that macrophages are not the only phaogocytic cells in the inner ear, but that supporting cells of the sensory epithelium also play an important role in debris clearance. We describe the various ways in which the sensory epithelia of the inner ear are adapted to eliminate damaged and dying cells. A collaborative effort between resident and migratory macrophages as well as neighboring supporting cells results in the rapid and efficient clearance of cellular debris, even in cases where hair cell loss is rapid and complete.
耳蜗和前庭器官中存在驻留巨噬细胞，但其在内耳维持和病理过程中的作用尚不完全清楚。其他器官中的驻留巨噬细胞负责吞噬受损或感染的细胞，内耳中的巨噬细胞可能也发挥类似作用。毛细胞损伤会导致巨噬细胞在内耳受损区域附近积聚，其方式要么是离开血管进入迷路，要么是驻留巨噬细胞通过局部移动重新组织至损伤区域。在多种情况下已观察到巨噬细胞吞噬凋亡毛细胞的直接证据。在此，我们回顾已发表文献以及本文作为原创工作展示的一些新实验中关于组织巨噬细胞吞噬感觉上皮中受损毛细胞的证据。多项研究还表明，巨噬细胞并非内耳中唯一的吞噬细胞，感觉上皮的支持细胞在碎片清除中也发挥重要作用。我们描述了内耳感觉上皮适应清除受损和濒死细胞的各种方式。驻留和迁移巨噬细胞以及相邻支持细胞之间的协同作用导致细胞碎片的快速有效清除，即使在毛细胞快速且完全丧失的情况下亦是如此。
