Crafoord S, Dafgård Kopp E, Seregard S, Algvere P V
Department of Ophthalmology, Orebro Medical Center, Sweden.
Graefes Arch Clin Exp Ophthalmol. 2000 Aug;238(8):682-9. doi: 10.1007/s004170000131.
In some retinal diseases and following transplantation of retinal pigment epithelium (RPE), melanin granules are liberated to the subretinal space. Our aim was to investigate the cellular response to implanted extracellular melanin.
After pars plana vitrectomy, 17 albino rabbits received a suspension of melanin granules in the subretinal space. Postoperative examination included ophthalmoscopy, color fundus photography, histology using monoclonal antibodies identifying RPE cells (AE1/3), macrophages (RAM 11), B-lymphocytes (CD20) and T-lymphocytes (CD45), and electron microscopy. The follow-up time was 2 weeks, 4 weeks and 6 months.
On fundus photographs, the layer of melanin showed focal attenuation with lighter areas at 6 months. Melanin granules were phagocytosed by RPE cells and macrophages at 2 weeks, as identified by monoclonal antibodies. In areas where an abundance of melanin was present, multilayers of macrophages were seen associated with considerable photoreceptor damage. Pigment-laden cells invaded the neural retina. The cellular infiltration of the retina was focal, and when it involved the outer nuclear layer the photoreceptor damage was severe. Electron microscopy demonstrated the presence of melanosomes intracellularly in Müller glia. The process of phagocytosis and removal of melanin granules from the subretinal space was slow and not completed at 6 months.
Our experiments show that implantation of melanin granules in the subretinal space of albino rabbits may induce a considerable phagocytic cellular response featuring the host's RPE, macrophages and glial cells. The migration of pigment-laden cells into the neural retina was associated with focal photoreceptor damage.
在一些视网膜疾病以及视网膜色素上皮（RPE）移植后，黑色素颗粒会释放到视网膜下间隙。我们的目的是研究细胞对植入的细胞外黑色素的反应。
经平坦部玻璃体切除术后，17只白化兔在视网膜下间隙接受了黑色素颗粒悬浮液。术后检查包括检眼镜检查、彩色眼底照相、使用识别RPE细胞（AE1/3）、巨噬细胞（RAM 11）、B淋巴细胞（CD20）和T淋巴细胞（CD45）的单克隆抗体进行组织学检查以及电子显微镜检查。随访时间为2周、4周和6个月。
在眼底照片上，黑色素层在6个月时出现局灶性变薄，有较浅区域。如通过单克隆抗体所识别，在2周时黑色素颗粒被RPE细胞和巨噬细胞吞噬。在存在大量黑色素的区域，可见多层巨噬细胞，伴有相当程度的光感受器损伤。含色素细胞侵入神经视网膜。视网膜的细胞浸润是局灶性的，当累及外核层时光感受器损伤严重。电子显微镜显示Müller胶质细胞内存在黑素小体。从视网膜下间隙吞噬和清除黑色素颗粒的过程缓慢，在6个月时未完成。
我们的实验表明，在白化兔的视网膜下间隙植入黑色素颗粒可能会诱导以宿主RPE、巨噬细胞和神经胶质细胞为特征的相当程度的吞噬细胞反应。含色素细胞向神经视网膜的迁移与局灶性光感受器损伤相关。
