Warboys Christina M, Toh Hong-Boon, Fraser Paul A
Cardiovascular Division, King's College London, London, United Kingdom.
Invest Ophthalmol Vis Sci. 2009 Mar;50(3):1319-28. doi: 10.1167/iovs.08-2730. Epub 2008 Nov 7.
The accumulation of advanced glycation end products (AGEs) within the retina in diabetes is associated with a chronic increase in retinal microvascular permeability. Isolated perfused retinas were used to examine the acute effects of AGEs on retinal microvascular permeability.
Retinas were dissected from eyes obtained from male Wistar rats, pinned out flat, and perfused with the low-molecular-weight fluorescent dye sulforhodamine B. Microvascular permeability was determined from the rate of decrease in fluorescence gradient across a vessel under conditions of zero flow. The production of reactive oxygen species (ROS) in JG2.1 retinal endothelial cells was also assessed with a fluorescent probe working solution.
A 30-second application of AGE-modified bovine serum albumin (AGE-BSA) to the abluminal surface of the retinal vasculature produced a rapid dose-dependent increase in retinal capillary permeability that was inhibited by pretreatment with anti-RAGE IgG. The permeability response also required ROS generated by NADPH oxidase because pretreatment with apocynin and the free radical scavengers superoxide dismutase and catalase significantly reduced the response. Pretreatment with calphostin C, SKF-96365, and U-73122 also significantly reduced the permeability response. In addition, the permeability response to bradykinin increased permeability through ROS and was potentiated after pretreatment with AGE-BSA. This potentiation was blocked by apocynin.
Acute activation of NADPH oxidase by phospholipase C-mediated activation of Ca(2+)-dependent PKC occurs downstream of RAGE activation to acutely increase retinal capillary permeability in the isolated perfused rat retina.
糖尿病患者视网膜内晚期糖基化终末产物（AGEs）的积累与视网膜微血管通透性的慢性增加有关。采用离体灌注视网膜来研究AGEs对视网膜微血管通透性的急性影响。
从雄性Wistar大鼠的眼睛中分离视网膜，平铺固定，并用低分子量荧光染料磺罗丹明B进行灌注。在零流量条件下，根据血管上荧光梯度的下降速率来测定微血管通透性。还用荧光探针工作溶液评估了JG2.1视网膜内皮细胞中活性氧（ROS）的产生。
向视网膜脉管系统的腔外表面施加30秒的AGE修饰牛血清白蛋白（AGE-BSA）可使视网膜毛细血管通透性迅速出现剂量依赖性增加，而抗RAGE IgG预处理可抑制这种增加。通透性反应还需要NADPH氧化酶产生的ROS，因为阿朴吗啡以及自由基清除剂超氧化物歧化酶和过氧化氢酶预处理可显著降低该反应。钙磷蛋白C、SKF-96365和U-73122预处理也显著降低了通透性反应。此外，对缓激肽的通透性反应通过ROS增加通透性，并且在AGE-BSA预处理后增强。这种增强被阿朴吗啡阻断。
在分离的灌注大鼠视网膜中，磷脂酶C介导的Ca(2+)依赖性蛋白激酶C激活导致NADPH氧化酶急性激活，发生在RAGE激活的下游，从而急性增加视网膜毛细血管通透性。
