Neuhardt T, May C A, Wilsch C, Eichhorn M, Lütjen-Drecoll E
Department of Anatomy II, University of Erlangen-Nürnberg, Erlangen, 91054, Germany.
Exp Eye Res. 1999 Jan;68(1):75-83. doi: 10.1006/exer.1998.0589.
The sequence of degenerative changes in the retinal pigment epithelium (RPE) and the choroid of retinal degeneration (rd)-mice was studied in correlation with photoreceptor changes. Three weeks to 26-month-old animals were investigated using light and transmission electron microscopy, enzyme histochemistry and quantitative morphology. Changes in the choriocapillaris (CC) were additionally studied by scanning electron microscopy of corrosion cast preparations. In 3-week-old mice, in which most of the outer segments of photoreceptors in the central portion of the retina had disappeared but remnants of the cells were still present, the RPE was enlarged and showed elongated microvilli. In 8-week-old animals, the photoreceptors were completely absent in large areas of the posterior pole region. In these areas the RPE was also completely lost. Quantitative evaluation performed in histological serial sections showed that loss of RPE measured as length of RPE-free Bruch's membrane, continuously increased up to the age of 20 months. In 8-week-old animals, CC adjacent to degenerating RPE showed loss of fenestration. In 10-week-old animals, the CC disappeared in those areas where the RPE was already lacking. The loss of CC increased with increasing age and in 20-month-old animals 5-10% of the entire CC was lacking. Loss of the related arterioles and nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d)-positive nerve fibers occurred only in approximately 2-year-old rd-mice. Compared to other animal models, RPE and CC defects in rd-mice are relatively large. The rd-mice might therefore provide a good tool to study factors involved in CC degeneration.
研究了视网膜色素上皮（RPE）和视网膜变性（rd）小鼠脉络膜的退行性变化序列，并与光感受器变化相关联。使用光学显微镜和透射电子显微镜、酶组织化学和定量形态学方法对3周龄至26月龄的动物进行了研究。通过腐蚀铸型制剂的扫描电子显微镜对脉络膜毛细血管（CC）的变化进行了额外研究。在3周龄的小鼠中，视网膜中央部分的光感受器大部分外段已经消失，但细胞残余仍然存在，RPE增大并显示出伸长的微绒毛。在8周龄的动物中，后极区域的大片区域光感受器完全缺失。在这些区域，RPE也完全丧失。在组织学连续切片中进行的定量评估表明，以无RPE的布鲁赫膜长度衡量的RPE丧失持续增加，直至20月龄。在8周龄的动物中，与退变的RPE相邻的CC显示出窗孔丧失。在10周龄的动物中，在RPE已经缺失的区域CC消失。CC的丧失随年龄增长而增加，在20月龄的动物中，整个CC的5%-10%缺失。相关小动脉和烟酰胺腺嘌呤二核苷酸磷酸黄递酶（NADPH-d）阳性神经纤维的丧失仅发生在约2岁的rd小鼠中。与其他动物模型相比，rd小鼠中的RPE和CC缺陷相对较大。因此，rd小鼠可能为研究参与CC退变的因素提供一个良好的工具。
