视觉发育关键期大鼠视网膜频域OCT测量值的变化特征

摘要

Background Retinal development continues during the early postnatal period in mammals.Correct arrangement of layers and precise location of various cells in the retina are vital for forming normal visual function during critical period plasticity.Spectral-domain optical coherence tomography(SD-OCT)provides highquality in vivo retinal imaging and the possibility to measure retinal thickness longitudinally. Objective The present study was to investigate the changes of retinal thickness during critical period plasticity in rats. Methods In vivo consecutive scanning of retinal image was performed in 10 SPF Sprague-Dawley rats at postnatal day 14(P14),P18,P21,P24 and P42 with SD-OCT,and retinal histopathological examination was used to detect retinal morphologic changes at the same postnatal ages in 20 matched rats.The whole retinal thickness,the thickness from inner limiting membrane(ILM)to inner plexiform layer(IPL),the thickness of inner nuclear layer(INL)and the thickness from outer nuclear layer(ONL)to retinal pigment epithelium(RPE)were measured using Cirrus HD-OCT system and HMIAS-2000 Imaging System in retinal sections.The measurement parameters by Cirrus HD-OCT and those by hematoxylin-eosin staining were compared.The use of animals followed the Statement of National Institute of Health (USA). Results In vivo high-resolution images of rat retinas with SD-OCT compared well with histology,which enabled quantitative comparison of the SD-OCT and histological data during critical period plasticity in rats.From P14 to P42,the retinal thickness gradually decreased with the increase of rat ages(F=15.425,P=0.000),and so were the thickness from ILM to IPL,the thickness of INL and the thickness from ONL to RPE(F=3.973,P=0.007;F=17.529,P=0.000;F=7.038,P=0.000).The retinal thickness,thickness of INL.thickness from ONL to RPE measured by Cirrus HD-OCT were significantly correlated with those measured by retinal sections among P14,P18,P21,P24 and P42 rats(r=0.794,P=0.000;r=0.784,P=0.000;r=0.681,P=0.000). Conclusion SD-OCT is a demonstratably valuable technology to study the structure of retinas in rats.The retinal thickness is shown to reduce in thickness throughout the development of the retina during critical period plasticity due to the decrease in thickness of INL and the distance from the ONL to RPE,as illustrated by OCT scanning.%背景人类和哺乳动物视觉发育关键期内视网膜处于发育阶段,其各个亚层的正确排列以及细胞的准确定位是视觉信息正常传递的基础之一.频域光学相关断层扫描(SD-OCT)可活体测量并连续观察大鼠视网膜厚度的变化.目的了解视觉发育关键期内SD大鼠视网膜厚度的变化规律.方法选择新生SD大鼠30只,其中10只于出生后14、18、21、24、42 d进行双眼眼底SD-OCT扫描,对视网膜厚度以及部分亚层包括内界膜(ILM)至内丛状层(IPL)、内核层(INL)、外核层(ONL)至视网膜色素上皮(RPE)层的厚度进行生物测量.另取20只SD大鼠,分别于14、18、21、24、42 d各处死4只大鼠并摘除双眼,制作石蜡切片行苏木精-伊红染色,对视网膜厚度以及部分亚层结构进行测量.并对两种方法测量数据的相关性进行评价.结果大鼠视网膜Cirrus HD-OCT图像由内向外可显示视网膜IPL、INL、外丛状层(OPL)、ONL、光感受器内节/外节(IS/OS)层以及RPE层等结构.比较各个时间点的视网膜厚度、ILM至IPL厚度、INL厚度以及ONL至RPE层厚度,差异均有统计学意义(F=15.425,P=0.000;F=3.973,P=0.007;F=17.529,P=0.000;F=7.038,P=0.000).随大鼠日龄的增加,视网膜厚度、INL厚度及ONL至RPE层厚度均呈递减趋势.测量视网膜组织切片各对应层次厚度,并与OCT测量结果进行线性回归分析,结果表明两种方法测量的视网膜厚度、INL厚度以及ONL至RPE层厚度均呈正相关(r=0.794,P=0.000;r=0.784,P=0.000;r=0.681,P=0.000).结论 Cirrus HD-OCT可以清晰地显示并测量大鼠视网膜各主要层次,且与组织学测量具有较好的相关性.视觉发育关键期内大鼠视网膜逐渐变薄,OCT测量主要表现为INL厚度和ONL至RPE层厚度减少.