VEGF-B及其受体Flt-1在氪激光诱导的大鼠脉络膜新生血管中的表达

Expression of vascular endothelial growth factor-B and its receptor Flt-1 in experimental choroidal neovascularization of rats

目的 研究血管内皮生长因子 B(vascularendothelialgrowthfactor B ,VEGF-B)及其受体Flt-1(fms liketyrosinekinase 1,Flt-1)在氪激光诱导的棕色挪威(BrownNorway ,BN)大鼠脉络膜新生血管(choroidalneovascularization ,CNV)形成中的作用机制。方法 应用氪激光(6 4.7nm ,36 0mW ,5 0 μm ,0 .0 5s)对实验组15只BN大鼠双眼进行眼底光凝。对照组15只大鼠只散瞳不光凝。2组分别于光凝后7d、14d、2 8d、5 6d、84d行眼底荧光血管造影(fundusfluoresceinangiography ,FFA) ,然后摘除眼球制作标本进行免疫组织化学检测VEGF-B和Flt-1,原位杂交检测VEGF BmRNA。结果 VEGF BmRNA在正常BN大鼠视网膜神经节细胞层、内核层、色素上皮层、视网膜和脉络膜血管内皮细胞表达。实验眼光凝后7d ,在激光损伤区VEGF BmRNA表达于视网膜神经节细胞层、内核层、外核层缺损区、视网膜和脉络膜血管内皮细胞及CNV增殖区,14d时CNV增殖区VEGF BmRNA阳性细胞染色密度最高(P <0 .0 1) ,1月后变化差异不显著(P >0 .1)。VEGF-B蛋白质与VEGF BmRNA的表达部位及趋势相同。Flt-1在正常视网膜色素上皮细胞、外界膜及外丛状层有阳性表达,视细胞层内侧及外核层有轻度着染。实验眼光凝7d后,Flt-1在神经节细胞层、内核层、外核层缺损区及CNV增?

Objective To study the pathogenesis that vascular endothelial growth factor-B (VEGF-B) and its receptor Flt-1 act in krypton laser-induced choroidal neovascularization of Brown Norway (BN) rat.Methods The experimental eyes of thirty anesthetized male BN rats received krypton laser(647 nm,360 mW,50 μm,0.05 s)lesions to induce CNV.Fundus fluorescein angiography examinations occurred just before euthanasia on day 7,14,21,28,56 and 84 after laser photocoagulation.The retina was processed for immunohistochemistry of VEGF and Flt-1 and in situ hybridization of VEGF mRNA.Results VEGF-B mRNA expression was mainly observed in the vascular endothelial cells,the ganglion cells,the inner nuclear layers,the retinal pigment epithelial cells in normal retina and the vascular endothelial cells of normal choroid of BN rat.VEGF-B mRNA expressed in the ganglion cells,the inner nuclear layers,lesion of outer nuclear layers in retina on the day 7 after photocoagulation.The level of VEGF-B mRNA expression was the highest on the day 14(P<0.01) in retina and decreased after one month(P>0.1).The expression of VEGF-B protein was the same as VEGF-B mRNA.Flt-1 was detected in the normal retinal pigment epithelial cells,external limiting membrane and outer plexiform.It presented in the same region as the VEGF-B's positive region.The level of expression increased during the development of CNV (P<0.01) and didn't significantly change after one month(P>0.1).Conclusion VEGF-B and Flt-1 combined in the place where choroidal neovascularization form by the autocrine and paracrine way.Flt-1 was phosphorylated.They mediate the differentiation of endothelial cells and the formation of CNV.