Department of Ophthalmology, Columbia University, New York, NY 10032, USA.
Graefes Arch Clin Exp Ophthalmol. 2010 Jul;248(7):973-84. doi: 10.1007/s00417-010-1325-x. Epub 2010 Mar 2.
To examine structural differences in the retinal pigmented epithelium (RPE) and Bruch's membrane of rhesus monkeys (Macaca mulatta) as a function of topography and age.
The retinas of two old (24 and 26 years old) and two young (1 and 6 years old) female monkeys were examined by light fluorescence and electron microscopy at the macula, equator, and ora serrata.
All monkeys lacked fluorescence and lipofuscin granules in the RPE at the ora serrata where photoreceptors are absent. The equator and macula showed intense fluorescence and many lipofuscin granules in the RPE of the old but not the young monkeys. At the ora, the RPE contained many dense round melanin granules throughout the cell. At the equator and macula, melanin granules were more apical, less frequent, and often elongated. Mitochondria were clustered at the basal side of the RPE cell near infolds of the plasma membrane. Both mitochondria and infolds tended to increase toward the macula. In all regions, the basal lamina of the RPE did not penetrate the extracellular space adjacent to infolds. The elastin layer of Bruch's membrane was wide at the ora and equator and thinner at the macula. In the old monkeys, drusen were found at all retinal regions between the basal lamina and the internal collagen layer of Bruch's membrane. The drusen were often membrane-bound with a basal lamina and contained material resembling structures in the RPE.
Lack of fluorescence and lipofuscin in the RPE at the ora serrata, where photoreceptors are absent, confirms that RPE fluorescence occurs only where outer segments are phagocytized. Mitochondrial clustering indicates that the basal side of the RPE cell uses the most energy and this becomes maximal at the macula. The presence of age-related degenerative changes and drusen at all retinal locations in the older monkeys, even at the ora where RPE lipofuscin was absent, indicates that these processes are not dependent on local lipofuscin accumulation. Therefore lipofuscin toxicity may not be the sole cause of age-related RPE degeneration.
研究恒河猴（Macaca mulatta）视网膜色素上皮（RPE）和 Bruch 膜的结构差异，以探讨其与眼位和年龄的关系。
用光荧光和电子显微镜观察两只老年（24 岁和 26 岁）和两只年轻（1 岁和 6 岁）雌性猕猴的黄斑、赤道和锯齿缘视网膜。
所有猴子的锯齿缘（该处无感光细胞）RPE 均无荧光和脂褐素颗粒。赤道和黄斑的老年猴 RPE 有强烈的荧光和大量脂褐素颗粒，但年轻猴 RPE 无此现象。在锯齿缘，RPE 细胞内有许多密集的圆形黑色素颗粒。赤道和黄斑的黑色素颗粒更靠近细胞顶部，数量更少，且常呈拉长状。线粒体聚集在靠近质膜内褶的 RPE 细胞基底侧。线粒体和内褶都有向黄斑移动的趋势。在所有区域，RPE 的基底层都没有穿过紧邻内褶的细胞外间隙。Bruch 膜的弹力层在锯齿缘和赤道处较宽，在黄斑处较薄。在老年猴中，所有视网膜区域的基底层和 Bruch 膜内层胶原之间都发现有玻璃膜疣。玻璃膜疣常与基底层结合，含有类似 RPE 结构的物质。
在无感光细胞的锯齿缘 RPE 缺乏荧光和脂褐素，证实了 RPE 荧光仅发生在外节被吞噬的部位。线粒体聚集表明 RPE 细胞的基底侧需要最大的能量，而黄斑处的能量需求最大。在老年猴的所有视网膜部位，包括在无 RPE 脂褐素的锯齿缘，都存在与年龄相关的退行性改变和玻璃膜疣，这表明这些过程并不依赖于局部脂褐素的积累。因此，脂褐素毒性可能不是与年龄相关的 RPE 变性的唯一原因。
