Centre for Ophthalmology and Visual Science, University of Western Australia, , Crawley, Western Australia, Australia.
Br J Ophthalmol. 2013 Oct;97(10):1343-50. doi: 10.1136/bjophthalmol-2013-303201. Epub 2013 Aug 2.
To evaluate the impact of systemic exposure to bacterial lipopolysaccharide (LPS) on a rodent model of background diabetic retinopathy.
Toll-like receptor 4 (TLR4)-mediated systemic inflammation was induced in Ins2(Akita) heterozygotes and age-matched C57BL6/J-Ins2(+) littermates by single or repeated intraperitoneal injections of the TLR4 ligand LPS (9 µg/g body weight). 24 hours after a single injection in 7-week-old mice retinal Il1b, Tnfa and Vegf transcripts were measured with real-time PCR. Vascular endothelial growth factor (VEGF) protein levels were evaluated with bead-based immunoassay. Leukostasis and endothelial injury were assessed in retinal wholemounts following perfusion with rhodamine or FITC conjugated concanavalin A to label leukocytes and propidium iodide to label dead or injured cells. In mice which had received three fortnightly injections between 10 and 16 weeks of age, retinal thicknesses and vascular structure were evaluated at 17-18 weeks of age using optical coherence tomography (OCT) and fluorescein angiography. Retinal architecture was assesed using resin-based histology.
Compared with normoglycaemic controls, systemic LPS exposure in Ins2(Akita) mice was associated with a 3.5-fold increase in endothelial cell injury and attenuated leukostasis in the retinal vasculature. Hyperglycaemia or acute LPS inflammation did not increase retinal VEGF content. Thinning (10-13 µm) of posterior retina was detected with OCT 2 weeks after repeated exposure to LPS in Ins2(Akita) mice but not in normoglycaemic controls. Capillary networks and retinal morphology were unaffected by recurrent LPS inflammation in Ins2(Akita) and control mice.
In hyperglycaemic mice, exposure to systemic LPS was associated with two hallmark pathologies of early background diabetic retinopathy, namely, the injury of capillary endothelium and in vivo thinning of the retina.
评估全身暴露于细菌脂多糖 (LPS) 对背景糖尿病性视网膜病变啮齿动物模型的影响。
通过单次或重复腹腔内注射 TLR4 配体 LPS（9μg/g 体重），诱导 Ins2(Akita) 杂合子和年龄匹配的 C57BL6/J-Ins2(+) 同窝仔鼠 TLR4 介导的全身炎症。在 7 周龄小鼠中，单次注射后 24 小时，使用实时 PCR 测量视网膜 Il1b、Tnfa 和 Vegf 转录本。使用基于珠的免疫测定法评估血管内皮生长因子 (VEGF) 蛋白水平。用 rhodamine 或 FITC 缀合的刀豆球蛋白 A 灌注视网膜全层，标记白细胞，并使用碘化丙啶标记死亡或受损细胞，评估白细胞增多和内皮损伤。在 10 至 16 周龄期间接受三次两周注射的小鼠中，在 17-18 周龄时使用光学相干断层扫描 (OCT) 和荧光血管造影评估视网膜厚度和血管结构。使用基于树脂的组织学评估视网膜结构。
与正常血糖对照组相比，Ins2(Akita) 小鼠全身 LPS 暴露与内皮细胞损伤增加 3.5 倍和视网膜血管中白细胞增多减少有关。高血糖或急性 LPS 炎症不会增加视网膜 VEGF 含量。在 Ins2(Akita) 小鼠重复暴露于 LPS 后 2 周，通过 OCT 检测到后视网膜变薄（10-13μm），但在正常血糖对照组中未检测到。反复 LPS 炎症对 Ins2(Akita) 和对照小鼠的毛细血管网络和视网膜形态没有影响。
在高血糖小鼠中，全身 LPS 暴露与背景糖尿病性视网膜病变的两个早期标志性病理有关，即毛细血管内皮损伤和体内视网膜变薄。
