James C R, Cotlier E
Br J Ophthalmol. 1983 Feb;67(2):80-8. doi: 10.1136/bjo.67.2.80.
A system for whole-blood perfusion of the bovine eye through the cilioretinal artery was developed and the distribution and binding of 125I-labelled insulin and human growth hormone (HGH) were studied autoradiographically. Sodium fluorescein was used as a tracer to monitor blood retinal barrier integrity, and electron microscopy was used to determine structural preservation after perfusion fixation. With this system, barrier integrity and structural perservation of both the neural retina and the retinal blood vessels were regularly obtained, with perfusion periods of as long as 5 hours. By quantitative light microscopy autoradiography, insulin binding sites were identified on the endothelial cells of retinal capillaries after perfusion with blood containing 125I-insulin. 125I-insulin binding was competitively inhibited by the addition of unlabelled insulin to the perfusing blood. By contrast the low level of binding of HGH to retinal capillaries was nonspecific. Electron microscopy autoradiography revealed 125I-insulin autoradiographic grains lying over the endothelial cell wall, over pinocytotic vesicles, and over the cytoplasm of both endothelial cells and pericytes. This suggests that, after binding to the cell surface, some insulin passes into the cell cytoplasm. However, neither 125I-HGH penetrated as far as the retina in the periods studied.
开发了一种通过睫状视网膜动脉对牛眼进行全血灌注的系统，并通过放射自显影研究了¹²⁵I标记的胰岛素和人生长激素（HGH）的分布与结合情况。使用荧光素钠作为示踪剂来监测血视网膜屏障的完整性，并利用电子显微镜确定灌注固定后的结构保存情况。利用该系统，在长达5小时的灌注期内，可定期获得神经视网膜和视网膜血管的屏障完整性及结构保存情况。通过定量光学显微镜放射自显影，在用含¹²⁵I胰岛素的血液灌注后，在视网膜毛细血管内皮细胞上鉴定出胰岛素结合位点。向灌注血液中添加未标记的胰岛素可竞争性抑制¹²⁵I胰岛素的结合。相比之下，HGH与视网膜毛细血管的低水平结合是非特异性的。电子显微镜放射自显影显示，¹²⁵I胰岛素放射自显影片颗粒位于内皮细胞壁、胞饮小泡以及内皮细胞和周细胞的细胞质上。这表明，胰岛素与细胞表面结合后，一些胰岛素进入细胞质。然而，在所研究的时间段内，¹²⁵I - HGH均未深入到视网膜。
