Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8096, St. Louis, MO 63110, USA.
Prog Retin Eye Res. 2021 May;82:100902. doi: 10.1016/j.preteyeres.2020.100902. Epub 2020 Sep 25.
The Zonule of Zinn, or ciliary zonule, is the elaborate system of extracellular fibers that centers the lens in the eye. In humans, the fibers transmit forces that flatten the lens during the process of disaccommodation, thereby bringing distant objects into focus. Zonular fibers are composed almost entirely of 10-12 nm-wide microfibrils, of which polymerized fibrillin is the most abundant component. The thickest fibers have a fascicular organization, where hundreds or thousands of microfibrils are gathered into micrometer-wide bundles. Many such bundles are aggregated to form a fiber. Dozens of proteins comprise the zonule. Most are derived from cells of the non-pigmented ciliary epithelium in the pars plana region, although some are probably contributed by the lens and perhaps other tissues of the anterior segment. Zonular fibers are viscoelastic cables but their component microfibrils are rather stiff structures. Thus, the elastic properties of the fibers likely stem from lateral interactions between microfibrils. Rupture of zonular fibers and subsequent lens dislocation (ectopia lentis) can result from blunt force trauma or be a sequela of other eye diseases, notably exfoliation syndrome. Ectopia lentis is also a feature of syndromic conditions caused typically by mutations in microfibril-associated genes. The resulting ocular phenotypes raise the possibility that the zonule regulates lens size and shape, globe size, and even corneal topology, in addition to its well-recognized role in accommodation.
Zonule of Zinn，也称为睫状小带，是一种精细的细胞外纤维系统，可将眼睛中的晶状体保持在中心位置。在人类中，纤维传递的力可在调节松弛过程中使晶状体变平，从而使远处的物体聚焦。带状纤维几乎完全由 10-12nm 宽的微纤维组成，其中聚合的原纤维蛋白是最丰富的成分。最粗的纤维具有束状组织，其中数百或数千根微纤维聚集在一起形成宽约 1 微米的束。许多这样的束被聚集形成纤维。带状纤维由数十种蛋白质组成。大多数来源于无色素睫状上皮细胞的扁平部，但有些可能是由晶状体和前节的其他组织贡献的。带状纤维是粘弹性电缆，但它们的组成微纤维是相当硬的结构。因此，纤维的弹性特性可能源于微纤维之间的侧向相互作用。带状纤维的破裂和随后的晶状体脱位（晶状体异位）可能是钝力创伤的结果，也可能是其他眼部疾病的后遗症，特别是剥脱综合征。晶状体异位也是由微纤维相关基因突变引起的综合征的特征。由此产生的眼部表型表明，除了其在调节中的公认作用外，带状纤维还调节晶状体的大小和形状、眼球大小，甚至角膜拓扑结构。
