Rafferty N S, Zigman S, McDaniel T, Scholz D L
Department of Cell, Molecular, and Structural Biology, Northwestern University, Chicago, Illinois.
Cell Motil Cytoskeleton. 1993;26(1):40-8. doi: 10.1002/cm.970260105.
Ultraviolet radiation in the near range (UVA) causes lens opacification and disrupts the actin cytoskeleton in rabbit and gray squirrel lenses. Changes were noted using transmission electron microscopy of tangential sections and rhodaminephalloidin fluorescence microscopy of epithelial whole mounts of irradiated and unirradiated lenses, and corresponded with gross cataract formation. Irradiated lenses lacked microfilament polygonal arrays at the inner surface of the apical plasma membrane (i.e., in the cell pole next to the lens fibers) in lens epithelia of both species; a condensed actin bundle was present instead. This bundle, and scattered small actin clumps in the cytoplasm, were identified by immunogold TEM, using a specific antibody and a secondary antibody conjugated with colloidal gold. Similar techniques showed breakdown of tubulin and vimentin, but after longer intervals than for the breakdown of actin. Generalized cytologic damage was also present in epithelial cells, but not in the underlying cortical lens fibers. Damage began to occur after 4 hr of irradiation and became more severe with increased exposure. Shielded controls remained clear, had normal cytology and polygonal arrays, and no clumping of actin filaments.
近紫外辐射（UVA）会导致兔和灰松鼠晶状体浑浊，并破坏其肌动蛋白细胞骨架。通过对照射和未照射晶状体的切向切片进行透射电子显微镜观察以及对上皮全层进行罗丹明鬼笔环肽荧光显微镜观察，发现了这些变化，且这些变化与肉眼可见的白内障形成相对应。在这两个物种的晶状体上皮细胞中，照射后的晶状体在顶端质膜内表面（即靠近晶状体纤维的细胞极）缺乏微丝多边形阵列；取而代之的是一个浓缩的肌动蛋白束。使用特异性抗体和与胶体金偶联的二抗，通过免疫金透射电镜鉴定了这个束以及细胞质中散在的小肌动蛋白团块。类似技术显示微管蛋白和波形蛋白分解，但比肌动蛋白分解所需的时间间隔更长。上皮细胞中也存在广泛的细胞学损伤，但在下方的皮质晶状体纤维中未出现。照射4小时后开始出现损伤，且随着照射时间增加损伤变得更严重。屏蔽对照组的晶状体仍保持透明，细胞学正常且有多边形阵列，肌动蛋白丝无聚集。
