Haselton F R, Dworska E J, Hoffman L H
Department of Biomedical Engineering, School of Engineering, Vanderbilt University, Nashville, Tennessee 37235, USA.
Invest Ophthalmol Vis Sci. 1998 Aug;39(9):1676-84.
To examine the effects of high glucose concentrations on retinal endothelial permeability in an in vitro model of the retinal microvasculature.
The permeability of the endothelial barrier to small solutes was measured in a chromatographic cell column consisting of bovine retinal endothelial cells cultured on porous fibronectin-coated microcarriers. In each cell column, permeability changes were evaluated by comparing the treatment permeability response over time with the initial baseline permeability. Short-term (2-hour) barrier effects of glucose were examined by measuring permeability at 15-minute intervals after an increase in perfusate concentration from baseline (5.5 mM) to high (25 mM) glucose. Long-term (to 57 days) effects were tested by addition of 25 mM glucose to microcarrier cultures. The effect of glucose on beta-receptor signaling was tested by measuring its effect on the permeability decrease produced by 1 microM isoproterenol.
An increase from 5.5 mM to 25 mM glucose concentration did not change retinal endothelial cell monolayer permeability (n=6) during 2 hours. However, an increase in monolayer permeability was observed after 19 days (n=8) in the 25-mM glucose culture. Paralleling this time course, short-term exposure to 25 mM glucose did not prevent a decrease in permeability triggered by the beta-receptor agonist isoproterenol. However, the permeability effect of the agonist was blocked by long-term culture in 25 mM glucose. Permeability of retinal endothelial monolayers cultured in 5.5 mM glucose and treated with 1 microM isoproterenol decreased significantly to 0.71+/-0.06 of baseline (n=4; mean+/-SEM). However, permeability did not change in parallel cell columns made from microcarriers cultured in 25 mM glucose (0.97+/-0.2 of baseline permeability; n=4; mean+/-SEM).
High-glucose culture decreases the retinal endothelial barrier and blocks the response to beta-adrenergic receptors. This model may prove valuable in exploring other hypotheses of increased permeability associated with diabetic retinopathy or other retinal diseases that break down the retinal vascular barrier.
在视网膜微血管的体外模型中研究高糖浓度对视网膜内皮通透性的影响。
在由培养于多孔纤连蛋白包被的微载体上的牛视网膜内皮细胞组成的色谱细胞柱中，测量内皮屏障对小分子溶质的通透性。在每个细胞柱中，通过比较处理后的通透性随时间的变化与初始基线通透性来评估通透性变化。通过在灌注液浓度从基线（5.5 mM）增加到高糖（25 mM）后每隔15分钟测量通透性，来检测葡萄糖的短期（2小时）屏障效应。通过向微载体培养物中添加25 mM葡萄糖来测试长期（至57天）效应。通过测量其对1 microM异丙肾上腺素引起的通透性降低的影响，来测试葡萄糖对β受体信号传导的影响。
在2小时内，葡萄糖浓度从(5.5 mM)增加到(25 mM)并未改变视网膜内皮细胞单层的通透性（(n = 6)）。然而，在(25 mM)葡萄糖培养19天后（(n = 8)），观察到单层通透性增加。与这个时间进程一致，短期暴露于(25 mM)葡萄糖并不能阻止β受体激动剂异丙肾上腺素引发的通透性降低。然而，激动剂的通透性效应在(25 mM)葡萄糖中长期培养后被阻断。在(5.5 mM)葡萄糖中培养并用(1 microM)异丙肾上腺素处理的视网膜内皮单层的通透性显著降低至基线的(0.71±0.06)（(n = 4)；平均值±标准误）。然而，在由(25 mM)葡萄糖培养的微载体制成的平行细胞柱中，通透性没有变化（基线通透性的(0.97±0.2)；(n = 4)；平均值±标准误）。
高糖培养降低了视网膜内皮屏障，并阻断了对β肾上腺素能受体的反应。该模型在探索与糖尿病性视网膜病变或其他破坏视网膜血管屏障的视网膜疾病相关的通透性增加的其他假说方面可能具有价值。
