维速达尔光动力疗法诱导兔视网膜静脉阻塞的实验研究

目的利用维速达尔光动力疗法(photodynamic therapy,PDT)诱导建立兔视网膜静脉阻塞(retinal vein occlusion,RVO)的实验模型,为RVO实验研究奠定基础。方法 19只兔随机分为空白对照组(3只)、单纯激光组(3只)、单纯光敏剂组(3只)和PDT组(10只),PDT组利用维速达尔联合689nm激光诱导建立RVO模型。造模后通过眼底照相、荧光素眼底血管造影(fluorescence fundus angiography,FFA)、全视野视网膜电图(electroretinogram,ERG)及组织病理学检查观察视网膜形态和组织学变化。结果眼底照相及FFA显示,PDT组造模后1d均出现明显的RVO;造模后3d部分模型开始出现侧枝循环;造模后7d仍可见血栓栓塞于视网膜静脉内;造模后14d所有阻塞静脉再通。全视野ERG显示:与空白对照组相比,PDT组暗适应3.0ERG中b波潜伏期明显延长(t=3.56,P=0.016),且其振幅上升显著(t=4.03,P=0.010)。此外,暗适应3.0震荡电位(OPs)总波振幅较空白对照组增高明显(t=3.21,P=0.024)。病理学检查结果显示:PDT组造模后1d视网膜静脉内血栓形成,部分血管有淤血,视网膜组织水肿;造模后28d视网膜静脉内血栓消失,但视网膜结构紊乱,视网膜神经节细胞层、感光细胞层、色素上皮层均消失,且脉络膜血管消失,大量空泡形成。结论通过PDT诱导建立的兔RVO模型,经眼底照相、FFA、全视野ERG和组织病理学证实是成功的,且血栓持续时间较为持久,并与人类RVO病变的发病机制较为相似。

Experimental study on verteporfin photodynamic therapy induced retinal venous occlusion in rabbit models

Objective To establish the rabbit model of retinal venous occlusion (RVO) induced by verteporfin photodynamic therapy (PDT),and provide the basement for studying the RVO. Methods Nineteen rabbits were divided into blank control group (3 cases),single laser group (3 cases),single verteporfin group (3 cases) and PDT group (10 cases),in PDT group verteporfin and a krypton red laser with 689 nm were used to irradiate the RVO model.The retinal morphous and tissue changes were observed by fundus imaging,fluorescein fundus angiography (FFA),full-field electroretinogram (ERG) and histopathology. Results Fundus imaging and FFA indicated that all of the photodynamic therapy (PDT) models appeared RVO at one day after operation,the collateral circulation were extensively formed in some models at 3 days,there were sill thrombus in some retinal veins at 7 days,and all the block veins were recanalized at 14 days.In ERG examination,compared with blank control group,the latency of b wave of scotopic response 3.0 in PDT group was obviously prolonged(t=3.56,P=0.016),and the amplitude was ascended significantly(t=4.03,P=0.010).The amplitudes of OPs of scotopic response 3.0 were ascended significantly,there was statistical difference compared with blank control group(t=3.21,P=0.024).Histology examination showed the venous thrombus was formed at 1 day after operation in PDT group,the congestion was seen in some veins,and the retinal edema was appeared;At 28 days after operation,the venous thrombus was disappeared,but the retinal structure was irregular,the ganglion cell layer,photoreceptor cells layer and retinal pigment epithelium (RPE) were disappeared.Besides,the choriocapillaris vanished,and many vacuoles formed. Conclusion Through the fundus examination,FFA,ERG and histopathology examinations,the rabbit RVO model is successfully established,and the duration of the thrombus is longer than before.The PDT-verteporfin-induced rabbit RVO model has the same pathogenesis with human beings.