摘要背景 视网膜血管瘤增生(RAP)属于新生血管性年龄相关性黄斑变性(AMD)的一种亚型,国内报道较少.目的 探讨血脂异常的ApoE基因缺失(ApoE-/-)小鼠RAP情况及其机制.方法 采用随机数字表法将2月龄以C57BL/6为背景的ApoE-/-小鼠24只分为ApoE-/-高脂模型组和ApoE-/-普通饮食组,每组12只；另用2月龄C57BL/6小鼠12只普通饮食喂养作为对照(C57BL/6普通饮食组).ApoE-/-高脂模型组小鼠用高脂饲料喂养,普通饮食组小鼠均用普通饲料喂养.3个组小鼠喂养4个月后(6月龄)以过量麻醉法处死,摘取左眼球制备视网膜组织切片,采用免疫组织化学染色法观察并检测3个组小鼠视网膜色素上皮(RPE)细胞中血管内皮生长因子(VEGF)、视网膜外丛状层(OPL)中VEGF受体-2(VEGFR-2)含量、OPL微血管密度(MVD)及微血管面积(MVA),用小鼠右眼视网膜组织行Western blot检测,定量3个组小鼠视网膜中VEGF蛋白的表达.结果 ApoE-/-高脂模型组和ApoE-/-普通饮食组视网膜OPL中MVD分别为(20.67±3.20)个/视野和(19.50±1.87)个/视野,MVA分别为(626.49±120.99) μm2和(514.06±88.83) μm2,均比C57BL/6普通饮食组的(12.50±1.87)个/视野及(336.52±84.96) μm2明显增高,差异均有统计学意义(P＜0.01)；ApoE-/-高脂模型组RPE细胞中VEGF面积为(21 048±1849)μm2,明显大于C57B L/6普通饮食组的(17 116±2023) μm2,差异有统计学意义(P＜0.01),而ApoE-/-普通饮食组RPE细胞中VEGF面积为(17 854±2967) μm2,与C57BL/6普通饮食组比较差异无统计学意义(P＞0.05).ApoE-/-高脂模型组和ApoE-/-普通饮食组小鼠视网膜OPL内VEGFR-2面积分别为(12 193±3806) μm2和(11 969±3616) tm2,明显大于C57BL/6普通饮食组的(5387±2225) μm2,差异均有统计学意义(P＜0.01);ApoE-/-高脂模型组和ApoE-/-普通饮食组小鼠视网膜中VEGF蛋白的相对表达量(VEGF/β-actin)分别为1.51±0.32和1.17±0.39,明显高于C57BL/6普通饮食组的0.28±0.14,差异均有统计学意义(P＜0.01).结论 ApoE-/-小鼠视网膜中的VEGF含量及OPL中的VEGFR-2含量均增高,其视网膜OPL的MVD增加、MVA增大,与RAP发病有关.

abstractsBackground Retinal angiomatous proliferation (RAP) is a subtype of neovascular age-related macular degeneration (AMD).There are currently very few studies on RAP.Objective This study was to explore the pathogenic mechanism of RAP in apolipoprotein E-deficient (ApoE-/-) mice with dyslipidemia.Methods Twenty-four 2-month-old SPF ApoE-/-mice were randomly divided into the high fat diet group and the normal diet group,and twelve 2-month-old C57BL/6 mice received the normal diet as controls.A diet with a higher content of fat was given for 4 consecutive months in the high fat diet group,and normal diet was given in the same way in the mice of the normal diet group.The mice were sacrificed at 6 months of age.The expression of vascular endothelial growth factor (VEGF) in the retinal pigment epithelial (RPE) cells,the expression of vascular endothelial growth factor receptor-2 (VEGFR-2) in the outer plexiform layer (OPL),microvascular density (MVD) and microvascular area (MVA) in the OPL were examined by immunohistochemistry and semi-quantitatively by histopathology with the Mias 2000 Imaging Analyzer System.The expression of VEGF protein in the retina was examined by Western blot.Results The MVD in the retinal OPL were (20.67±3.20) and (19.50± 1.87),respectively,in the ApoE-/-mice of the high fat diet group and the normal diet group,which were significantly higher than that (12.50±1.87) of the C57BL/6 normal diet group (all at P＜0.01).MVA in the retinal OPL were (626.49± 120.99) μm2 and (514.06±88.83) μm2 in the ApoE-/-mice of the high fat diet group and the normal diet group,respectively,showing a significant increase in comparison with the (336.52±84.96) μm2 of the C57BL/6 normal diet group (P＜0.01).The staining area of VEGF in RPE cells was (21 048±1849) μm2 in the ApoE-/-mice of the high fat diet group,showing a significant increase in comparison with the (17 116±2023) μm2 of the C57BL/6 normal diet group.However,no significant difference was found in the staining area of VEGF between the ApoE-/-mice with normal diet group and the C57BL/6 normal diet group ([17 854±2967] μm2 vs.[17 116±2023] μm2) (P＞0.05).Significant elevation was also seen in the staining area of VEGFR-2 in the retinal OPL of the ApoE-/-mice of the high fat diet group (12 193±3806)μm2 and the ApoE-/-mice of the normal diet group (11 969± 3616)xm2 compared with C57BL/6 mice of the normal diet group (5387±2225)μm2(all at P＜0.01).The relative expression values (VEGF/β-actin) of VEGF in the retinas were (1.51 ±0.32) and (1.17±0.39) in the ApoE-/-mice of the high fat diet group and the normal diet group,respectively,showing a significant increase in comparison with (0.28±0.14) of the C57BL/6 normal diet group (P＜0.01).Conclusions The expression of VEGF and VEGFR-2 in the retinas increases in the ApoE-/-mouse,which leads to the enlargement of MVD and MVA in the retinal OPL and subsequent RAP occurrence.