532nm激光诱导棕色挪威大鼠脉络膜新生血管模型的研究与评价

Evaluation and optimization of 520 nm-laser-induced choroidal neovascularization in brown Norway rats

目的应用532nm激光采用2种方法诱导棕色挪威(BN)大鼠脉络膜新生血管(CNV)模型,以确定诱导CNV形成的最佳方法。方法将40只BN大鼠随机分为2个光斑组(20只,于每2个血管之间光凝2个光斑)和1个光斑组(20只,于每2个血管之间光凝1个光斑),另取20只大鼠作为空白对照组。所有大鼠分别于造模后第1、2、3、4周行眼底荧光血管造影(FFA)及光学相干断层扫描(OCT)检查,观察空白对照组大鼠视网膜情况及1个光斑组和2个光斑组大鼠造模后CNV的形成情况,记录渗漏光斑数(即CNV形成数目),比较1个光斑组与2个光斑组大鼠的渗漏率。再分别自3组大鼠中随机抽取1只取其左眼行苏木精-伊红(H-E)染色,观察空白对照组大鼠的视网膜脉络膜情况及1个光斑组和2个光斑组大鼠造模后CNV的形成情况。结果 FFA见,2个光斑组大鼠造模后第1、2、3、4周的光斑渗透率分别为45.54%(158/348)、63.03%(208/330)、66.67%(208/312)、29.93%(88/294),均较1个光斑组大鼠的56.49%(135/239)、79.29%(180/227)、81.40%(175/215)、53.20%(108/203)显著降低(P值均<0.05)。两个造模组CNV的渗漏高峰均出现于造模后2～3周;造模后第4周,2个光斑组FFA见大多数光斑已形成瘢痕;而1个光斑组光斑渗漏仍明显。OCT见,1个光斑组大鼠造模后第2周视网膜神经上皮增厚,视网膜色素上皮(RPE)复合层不连续,局部增厚,反射增强,界限不清;造模后第4周仍可见上述改变;2个光斑组大鼠造模后第4周视网膜神经上皮层变薄,RPE复合层不连续,局部见强反射,界限清晰。H-E染色示,1个光斑组造模后第2周,见色素上皮不完整,并可见色素上皮细胞移行,其间夹杂较多新生血管;2个光斑组造模后第4周,见视网膜各层明显变薄,色素上皮紊乱,有大量色素增殖,未见新生血管。结论 532nm激光可成功诱导BN大鼠CNV形成,2支血管之间光凝1个光斑后CNV模型的成模率较高。

Objective To evaluate and optimize the method of inducing choroidal neovascularization （CNV） model by 532 nm laser photocoagulation in Brown-Norway （BN） rat eyes. Methods Sixty BN rats were randomly divided into 3 groups （n = 20）： normal control group, group 1 （two photocoagulation spots were given between every 2 retinal vessels） and group＇2 Cone photocoagulation spot was given between every 2 retinal vessels）. Retinal photocoagulation spots were studied by fluorescein angiography （FFA） and OCT i.n week 1, 2, 3 and 4 after photocoagulation. Results The leakage rates of induced CNV in group 1 were 45.54% （ 158/348）, 63.03% （208/330）, 66-67% （208/312） and 29.93% （88/294） in week 1, 2, 3 and 4 after photocoagulation by FFA,＇respectively. The leakage rates in group 2 were 56. 49% （135/239）, 79. 29% （180/227）, 81.40% （175/215） and 53.20% （108/203） in week 1, 2, 3 and 4 after photocoagulation, respectively. The leakage rates in group 1 were significantly lower than group 2 （all P^0.05）. It was found that the best time for laser-induced ONV formation was 2-3 weeks after laser in both groups by FFA. OCT showed retinal neurepithelium thickening, and the discontinuity, local thickening, enhanced reflection and obscure boundary of retinal pigment epithelium （RPE） composite layer in group 2 in week 2~ and those changes could be seen until week 4. But in group 1, retinal neurepithelium thinningz, and the discontinuity, local high reflection, and clear boundary of RPE composite layer were found in the 4t＂ week. Incomplete RPE, transitional RPE cells, and more CNV were found in group 2 in week 2 by HE staining, and retinal thinningz, RPE disorder and none CNV were seen in group 1 in week 4. Conclusion CNV can be successfully induced by 532 nm laser in BN rats. The formulation of two photocoagulation spots between every 2 retinal vessels is an effective method for inducing CNV model.