Age-related changes on the surface of vitreous collagen fibrils
Age-related changes on the surface of vitreous collagen fibrils
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DOI：
10.1167/iovs.03-1017
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发表时间：
2004-04-01
影响因子：
4.4
通讯作者：
Bos, KJ
中科院分区：
文献类型：
--
作者：
Bishop, PN;Holmes, DF;Bos, KJ
目的。确定老化的玻璃体胶原原纤维是否经历可能导致玻璃体液化和玻璃体后脱离的超微结构变化。方法。在电子显微镜网格上分离出来自 21 名人类受试者（年龄范围为 3 - 89 岁）和牛眼的玻璃体胶原纤维。通过透射电子显微镜分析了 0.3 M MgCl2 存在下的铜粉蓝标记和 II 型和 IX 型胶原蛋白的免疫金标记。结果。衰老与人类玻璃体胶原纤维表面的显着变化有关，包括 IX 型胶原蛋白及其硫酸软骨素侧链呈指数损失（半衰期，11 年），以及 II 型胶原蛋白暴露量增加四倍。结论。尽管 IX 型胶原蛋白是玻璃体胶原原纤维的次要成分，但可能凭借其硫酸软骨素侧链，可以保护 II 型胶原蛋白免于暴露在原纤维表面。随着年龄的增长，这种屏蔽作用减弱，导致“粘性”II 型胶原蛋白表面暴露，从而使玻璃体胶原纤维易于融合。这些变化可能是玻璃体液化和玻璃体视网膜粘附减弱的基础。
PURPOSE. To determine whether aging vitreous collagen fibrils undergo ultrastructural changes that might underlie vitreous liquefaction and posterior vitreous detachment.METHODS. Vitreous collagen fibrils from 21 human subjects ( age range, 3 - 89 years) and from bovine eyes were isolated on electron microscopy grids. Cupromeronic blue labeling in the presence of 0.3 M MgCl2 and immunogold labeling for collagen types II and IX were analyzed by transmission electron microscopy.RESULTS. Aging was associated with marked changes on the surface of human vitreous collagen fibrils, including an exponential loss of type IX collagen along with its chondroitin sulfate side-chains ( half-life, 11 years) and a fourfold increase in the exposure of type II collagen.CONCLUSIONS. Despite being a minor component of vitreous collagen fibrils, type IX collagen, probably by virtue of its chondroitin sulfate side-chains, shields type II collagen from exposure on the fibril surface. With aging, this shielding diminishes, resulting in the surface exposure of "sticky" type II collagen and thus predisposing the vitreous collagen fibrils to fusion. These changes could underlie vitreous liquefaction and weakening of vitreoretinal adhesion.