Caldwell R B, Slapnick S M, McLaughlin B J
Invest Ophthalmol Vis Sci. 1986 Dec;27(12):1691-7.
The basal laminae of capillaries, glomeruli, and nerves are thickened in diabetes. Previous studies have shown that diabetic tissues produce increased levels of basal lamina collagen and reduced levels of proteoglycans. Since heparan sulfate and chondroitin sulfate proteoglycans are thought to act as anionic barriers regulating passage of proteins across Bruch's membrane of the eye, the cationic electron microscope tracers, polyethyleneimine (PEI) and ruthenium red, were used to study the distribution of anionic sites in Bruch's membrane of spontaneously diabetic Bio-Breeding/Worcester (BB-W) rats and streptozotocin-diabetic rats. The distribution of the two tracers is similar. In Bruch's membrane of control rats, electron dense particles are present at regular intervals along both sides of the basal laminae of the retinal pigment epithelium (RPE) and of the choriocapillary endothelium (CE), and along collagen fibers in the zone between the two basal laminae. Within 3-6 months after the onset of hyperglycemia in both diabetic rat models, quantitative analysis shows a significant reduction in binding sites along both RPE and CE basal laminae, while thickness of both basal laminae is significantly increased. Because reductions in anionic binding sites along basal laminae in the renal glomerulus have been found to accompany changes in glomerular filtration, these changes suggest that filtration through Bruch's membrane is altered in diabetes.
在糖尿病中，毛细血管、肾小球和神经的基底层会增厚。先前的研究表明，糖尿病组织中基底层胶原蛋白水平升高，蛋白聚糖水平降低。由于硫酸乙酰肝素和硫酸软骨素蛋白聚糖被认为可作为阴离子屏障，调节蛋白质穿过眼睛的布鲁赫膜，因此使用阳离子电子显微镜示踪剂聚乙烯亚胺（PEI）和钌红，来研究自发性糖尿病Bio-Breeding/Worcester（BB-W）大鼠和链脲佐菌素诱导糖尿病大鼠的布鲁赫膜中阴离子位点的分布。两种示踪剂的分布相似。在对照大鼠的布鲁赫膜中，电子致密颗粒沿视网膜色素上皮（RPE）和脉络膜毛细血管内皮（CE）基底层的两侧，以及两个基底层之间区域的胶原纤维，有规律地间隔出现。在两种糖尿病大鼠模型出现高血糖后的3至6个月内，定量分析显示RPE和CE基底层的结合位点显著减少，而两个基底层的厚度均显著增加。由于已发现肾小球基底层阴离子结合位点的减少与肾小球滤过的变化相关，这些变化表明糖尿病中通过布鲁赫膜的滤过发生了改变。
