Furness D N, Richardson G P, Russell I J
Department of Communication and Neuroscience, University of Keele, U.K.
Hear Res. 1989 Mar;38(1-2):95-109. doi: 10.1016/0378-5955(89)90131-7.
Organotypic cultures of the neonatal mouse cochlea have a band of hair cells consisting of 3-5 rows of outer hair cells and a single row of inner hair cells. The outer hair cell stereociliary bundles show progressive differentiation from the apical to the basal ends of the band. Undifferentiated apical bundles have a disk-like array of short stereocilia resembling microvilli. Partially differentiated bundles are hemispherical with poorly organized rows of thickly clustered stereocilia, which gradually increase in height in the direction of the kinocilium. More differentiated bundles remain hemispherical with many microvilli-like stereocilia, but have highly organized rows of sterocilia along the side nearest to the kinocilium, and well-defined height increments between the rows. Highly-differentiated, basal bundles usually have a 'V' or 'W' shape, although some can be almost polygonal. The basal bundles have 4-5 regular rows of stereocilia with a well-defined gradient in height across the rows, and very few microvilli-like stereocilia. Cross-links are only consistently observed in more differentiated bundles, where the rows of stereocilia are regular and have significant height increments across them. The links show a wide variety of forms and orientations not previously observed in other preparations. Spoke-like arrays of links project from the upper regions of many stereocilia and other stereocilia appear to bear distinct tip-to-side links, although with a variety of orientations. A similar variety of cross-links is observed in early postnatal cochleae in vivo, but not in the cochleae of adult mice, indicating that this variety may be a transient feature of sterociliary bundle development. In vitro, inner hair cell stereociliary bundles are often covered by overlying material from the developing tectorial membrane. The variations in morphology of inner hair cell bundles and their cross-links are similar to those of the outer hair cell bundles.
新生小鼠耳蜗的器官型培养物中有一排毛细胞，由3 - 5排外毛细胞和一排内毛细胞组成。外毛细胞静纤毛束从毛细胞带的顶端到基部呈现出逐渐分化的过程。未分化的顶端纤毛束有一排盘状的短静纤毛，类似于微绒毛。部分分化的纤毛束呈半球形，排列不规则，静纤毛密集丛生，沿动纤毛方向逐渐增高。分化程度更高的纤毛束仍为半球形，有许多微绒毛样静纤毛，但在最靠近动纤毛的一侧有排列高度有序的静纤毛排，且各排之间有明确的高度递增。高度分化的基部纤毛束通常呈“V”形或“W”形，不过有些几乎呈多边形。基部纤毛束有4 - 5排规则的静纤毛，各排之间高度有明确的梯度，且微绒毛样静纤毛极少。交叉连接仅在分化程度更高的纤毛束中持续观察到，这些纤毛束中的静纤毛排规则，且各排之间有显著的高度递增。这些连接呈现出多种形式和方向，在其他标本中未曾见过。从许多静纤毛的上部区域伸出轮辐状的连接阵列，其他静纤毛似乎有明显的尖端到侧面的连接，尽管方向各异。在出生后早期的体内耳蜗中也观察到类似的多种交叉连接，但成年小鼠的耳蜗中没有，这表明这种多样性可能是静纤毛束发育的一个短暂特征。在体外，内毛细胞静纤毛束常被发育中的盖膜覆盖物覆盖。内毛细胞束及其交叉连接的形态变化与外毛细胞束相似。
