Li Z Y, Possin D E, Milam A H
Department of Ophthalmology, University of Washington, Seattle.
Ophthalmology. 1995 May;102(5):805-16. doi: 10.1016/s0161-6420(95)30953-0.
To evaluate bone spicule pigmentation, a fundus feature in retinitis pigmentosa (RP) formed by migration of pigment-containing cells to perivascular sites in the inner retina.
The authors performed light and electron microscopy, including immunocytochemistry, on the retinas from ten patients with RP and five normal donors.
The pigment-containing cells in regions of bone spicule pigmentation were derived from the retinal pigment epithelium (RPE). The translocated cells were remarkably polarized with a number of specializations characteristic of RPE cells in situ, but they did not contain lipofuscin granules and were not immunoreactive for cellular retinaldehyde-binding protein. The cells were linked by junctional complexes and formed epithelial layers around retinal vessels and next to the inner limiting membrane. Adjacent Müller cell processes contained glial fibrillary acidic protein-positive filaments and formed microvilli and intermediate junctions, resembling those in the external limiting membrane. Vascular endothelial cells adjacent to the translocated RPE cells were thin and fenestrated, resembling the choriocapillaris, and were separated from the pigmented cells by a layer of extracellular matrix similar in organization to Bruch membrane. Thickening of the matrix layer caused narrowing and occlusion of the vascular lumina.
The lack of lipofuscin granules and cellular retinaldehyde-binding protein immunoreactivity in the translocated RPE cells is probably related to the loss of photoreceptors. The development of fenestrations in the endothelial cells correlates with the leakiness of retinal vessels to fluorescein observed in some cases of RP. Narrowing and occlusion of vascular lumina by thickening of the surrounding layer of extracellular matrix may contribute to the loss of inner retinal neurons found in RP. These changes in the RPE, blood vessels, glia, and inner neurons warrant consideration in designing therapies to restore vision to degenerate retinas.
评估骨针状色素沉着，这是视网膜色素变性（RP）中的一种眼底特征，由含色素细胞迁移至视网膜内层的血管周围部位形成。
作者对10例RP患者和5名正常供体的视网膜进行了光学显微镜和电子显微镜检查，包括免疫细胞化学检查。
骨针状色素沉着区域的含色素细胞来源于视网膜色素上皮（RPE）。迁移的细胞明显极化，具有一些原位RPE细胞特有的特化结构，但它们不含脂褐素颗粒，对细胞视黄醛结合蛋白无免疫反应性。细胞通过连接复合体相连，围绕视网膜血管并在内界膜旁形成上皮层。相邻的Müller细胞突起含有胶质纤维酸性蛋白阳性细丝，并形成微绒毛和中间连接，类似于外界膜中的结构。与迁移的RPE细胞相邻的血管内皮细胞薄且有窗孔，类似于脉络膜毛细血管，并且通过一层组织类似于Bruch膜的细胞外基质与色素细胞分隔开。基质层增厚导致血管腔狭窄和闭塞。
迁移的RPE细胞中缺乏脂褐素颗粒和细胞视黄醛结合蛋白免疫反应性可能与光感受器的丧失有关。内皮细胞窗孔的形成与某些RP病例中观察到的视网膜血管对荧光素的渗漏相关。周围细胞外基质层增厚导致血管腔狭窄和闭塞可能是RP中视网膜内层神经元丧失的原因。RPE、血管、神经胶质和内层神经元的这些变化在设计恢复退化视网膜视力的治疗方法时值得考虑。
