Smith S B, Cope B K, McCoy J R, McCool D J, Defoe D M
Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta 30912-2000.
Invest Ophthalmol Vis Sci. 1994 Sep;35(10):3625-32.
The vitiligo (C57BL/6-mivit/mivit) mouse has a slowly progressing retinal degeneration, in which photoreceptor cell nuclei are gradually lost and the retinal pigment epithelium (RPE) is unevenly pigmented. The purpose of the present study was to assess the phagocytic ability of the RPE in the vitiligo mouse by determining whether and when a phagocytic burst occurs in affected mice and whether the number of phagosomes varies between control and affected animals.
Eyes of control and vitiligo mice 4 to 20 weeks of age were embedded in Spurr. Thin sections were cut and examined by electron microscopy to confirm the presence of phagosomes, particularly in the affected animals. Thick (1 micron) sections were cut, and quantitative morphometry was performed at the light microscope level. The length of RPE was determined, and phagosomes were counted in RPE cytoplasmic and microvillous areas. Data were expressed as phagosomes per 1000 microns.
The vitiligo mouse has a peak phagocytic episode approximately 2 hours after light onset. The number of phagosomes in 4-week-old affected mice was significantly less than that in controls (13 phagosomes per 1000 microns compared to 30 phagosomes per 1000 microns). By week 8, the number was reduced to approximately 5 per 1000 microns. Phagosome number was not reduced further between weeks 8 and 20 in the affected animal. Macrophage-like cells containing pigment granules and phagosomes were observed in the subretinal space in areas where the rod outer segments had been separated from the RPE.
The vitiligo mouse RPE contains phagosomes, but there are significantly fewer than in controls. It is not known whether a defect in RPE phagocytosis is the direct cause of the retinal defect in this model.
白癜风（C57BL/6 - mivit/mivit）小鼠患有缓慢进展的视网膜变性，其中光感受器细胞核逐渐丢失，视网膜色素上皮（RPE）色素沉着不均。本研究的目的是通过确定受影响小鼠是否以及何时发生吞噬爆发以及对照动物和受影响动物之间吞噬体数量是否存在差异，来评估白癜风小鼠中RPE的吞噬能力。
将4至20周龄的对照小鼠和白癜风小鼠的眼睛包埋在Spurr树脂中。切成薄片并通过电子显微镜检查以确认吞噬体的存在，特别是在受影响的动物中。切成厚（1微米）的切片，并在光学显微镜水平进行定量形态学分析。确定RPE的长度，并在RPE细胞质和微绒毛区域计数吞噬体。数据以每1000微米的吞噬体数表示。
白癜风小鼠在光照开始后约2小时有一个吞噬高峰。4周龄受影响小鼠的吞噬体数量明显少于对照组（每1000微米13个吞噬体，而对照组为每1000微米30个吞噬体）。到第8周，数量减少到每1000微米约5个。在受影响动物中，第8周和第20周之间吞噬体数量没有进一步减少。在视网膜下空间中观察到含有色素颗粒和吞噬体的巨噬细胞样细胞，这些区域的视杆外段已与RPE分离。
白癜风小鼠的RPE含有吞噬体，但明显少于对照组。尚不清楚RPE吞噬缺陷是否是该模型中视网膜缺陷的直接原因。
