FFA及OCT对STZ诱导的早期糖尿病大鼠视网膜的活体观察

背景 链脲佐菌素（STZ）诱导的糖尿病SD大鼠是进行糖尿病视网膜病变（DR）发病机制研究常用的动物模型,以往主要用离体眼球进行观察,荧光素眼底血管造影（FFA）和光学相干断层扫描（OCT）技术可活体观察眼底,但目前FFA和OCT联合用于DR模型的观察尚未报道. 目的 将FFA和OCT联合用于STZ诱导的糖尿病SD大鼠的眼底检查,动态观察糖尿病模型早期阶段视网膜血管的渗漏及视网膜厚度的变化情况.方法 将60只清洁级SD大鼠按随机数字表法随机分为2个组,糖尿病组大鼠一次性腹腔内注射溶于柠檬酸钠溶液的STZ诱导糖尿病大鼠模型,对照组大鼠以同样的方式注射柠檬酸钠溶液.分别于造模前及造模成功后第4、8、12周在大鼠全身麻醉状态下采用FFA联合Spectralis HRA＋OCT（SD-OCT）动态观察和比较各组大鼠左眼视网膜血管的渗漏情况及视网膜厚度的变化情况.FFA检查时大鼠腹腔内注射质量分数20％荧光素钠（0.012 ml/g）并快速观察视盘及上方、下方、鼻侧、颞侧、鼻上、鼻下、颞上、颞下视网膜共9个方位的视网膜血管情况,OCT检查时测量距视盘上方、下方、鼻侧、颞侧2个视盘直径（DD）处的视网膜厚度.采用组织病理学检查测量视网膜厚度并与OCT测量结果进行比较.结果 FFA检查结果显示,大鼠的视盘位于视网膜中央,血管走行呈放射状.荧光素钠注射后60 s背景荧光消失,需重复注射.至造模成功后12周,各组大鼠视网膜均未发现荧光素渗漏.OCT结果显示,正常SD大鼠的OCT图像与人类相似,共分为十层,与组织病理学检测的结果相吻合.距视盘2 DD处上方、下方、鼻侧、颞侧4个方向视网膜厚度及内外界膜间的厚度比较差异均无统计学意义（P＞0.05）.造模后4周、8周,与对照组大鼠比较,糖尿病组大鼠视网膜厚度无明显增加,差异均无统计学意义（P＞0.05）;造模后12周糖尿病组大鼠的视网膜厚度和内外界膜间厚度与对照组大鼠比较均明显增加,差异均有统计学意义（P＜0.05）.OCT测量的视网膜厚度和内外界膜间量化分析结果与组织病理学结果并不完全一致. 结论 SD-OCT联合FFA有助于活体观察糖尿病大鼠视网膜厚度的动态变化,评估血管渗漏情况,为糖尿病的发病机制研究、防治及病情监测提供依据.

Evaluation of the vascular leakage and retina thickness using OCT combined with FFA in STZ-induced diabetic rat model

Background Streptozocin （STZ）-induced SD diabetic rat model is often used in the study of diabetic retinopathy （DR）.The research approach of retinas in DR model previously is in vitro study.Fluorescein fundus angiography（FFA） and optical coherence tomography （OCT） are available for the in vivo observation of ocular fundus.But the combination of FFA and OCT used to dynamic evaluation of DR is less well-known.Objective The purpose of this study was to investigate the changes of retinal vessel and capillary as well as retinal thickness in STZ-induced diabetic SD rat.Methods Sixty clean SD rats were randomized into two groups according to random number table.STZ dissolving in sodium citrate solution was intraperitoneally injected to establish diabetic animal models in the diabetic group,and equivalent amount of sodium citrate solution was used in the same way in the control group.FFA and Spectralis HRA＋OCT（SD-OCT） were used to dynamically identify the fluorescine leakage of retinal vessels and thickness of retinas in the superior,inferior,nasal and temporal retinas in the left eyes 4,8,12 weeks after injection.The use and care of experimental animals complied with the relative statement of National Institutes of Health （NIH,USA）.Results FFA exhibited that the optical disc located at the center of retina,and retinal vessels run in radical pattern.The choroidal fluorescence disappeared 60 seconds after intravenous injection of fluorescine sodium.So repeatedly injection was needed for multiple parts of imagine.No fluorescine leakage was found in rat retinas from initial until 12 weeks after modeling.OCT examination showed a similar imaging in SD rat to human,with 10 layers of tissues,which was consistent with those in histopathological image.No significant differences were found in retinal thickness as well as inner and outer limiting membrane thickness among the superior,inferior,nasal and temporal retina from 2 disc diameter （DD） away optical disc （P〉0.05）.Compared with normal SD rats,retinal thickness and inner and outer limiting membrane thickness were no significant difference 4,8 weeks after modeling （all at P〉0.05）,and retina and inner and outer limiting membrane in 12 weeks were thicker than those in normal rats （all at P 〈 0.05）.The analysis outcome from OCT was not totally consistent with that from histopathological examination.Conclusions Combination application of SD-OCT and FFA is helpful for the in vivo assessment of early DR of rat.