Hu Wenzheng, Criswell Mark H, Fong Shao-Ling, Temm Constance J, Rajashekhar Gangaraju, Cornell Tammy L, Clauss Matthias A
Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN 46202-5175, USA.
Exp Eye Res. 2009 Jan;88(1):79-91. doi: 10.1016/j.exer.2008.10.014. Epub 2008 Nov 1.
Although the roles of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and hepatocyte growth factor (HGF) in pathologic neovascularization have been well characterized in certain tissues, their particular functions and expression patterns in choroidal neovascularization (CNV) have not been clearly established. After localized laser trauma to Bruch's membrane to induce CNV development, the temporal changes in mRNA and protein expression of these 3 cytokines were documented and compared histologically to areas of immunofluorescence, the proliferation of endothelial cells, neovascular development, and temporal changes in vascular permeability. Changes in mRNA and protein levels of bFGF and HGF occurred quickly and reached peak expression within hours. This activity corresponded in time to intense and localized immunofluorescence for these cytokines within the choriocapillaris within laser lesion sites. During this same initial time period, mRNA upregulation of VEGF occurred, primarily within the neural retina and this expression corresponded to intense immunolabeling of Müller cells immediately adjacent to the lesion sites. By 3 days after lasering, increased VEGF(164) protein expression was measurable, whereas early neovascular development histologically corresponded to HGF and bFGF mRNA expansion into the developing choroidal neovascular membrane (CNVM). At 7 days, CNV expansion, maturation, and increased vascular permeability corresponded to peak VEGF mRNA and protein expression and to immunofluorescence of the CNVM. Differences also occurred in the expression of precursor and activated isoforms of these cytokines in the retinal pigment epithelium/choroid as compared to those in the retina. These molecular and immunocytochemical results suggest that bFGF and HGF may be important as initial regulators neovascularization in this CNV model; whereas VEGF may be important during later phases of angiogenesis and neovascular hyperpermeability.
尽管血管内皮生长因子（VEGF）、碱性成纤维细胞生长因子（bFGF）和肝细胞生长因子（HGF）在某些组织的病理性新生血管形成中的作用已得到充分表征，但它们在脉络膜新生血管形成（CNV）中的具体功能和表达模式尚未明确确立。在对 Bruch 膜进行局部激光损伤以诱导 CNV 发展后，记录了这三种细胞因子的 mRNA 和蛋白质表达的时间变化，并与免疫荧光区域、内皮细胞增殖、新生血管发育以及血管通透性的时间变化进行了组织学比较。bFGF 和 HGF 的 mRNA 和蛋白质水平变化迅速，并在数小时内达到峰值表达。这种活性在时间上与激光损伤部位脉络膜毛细血管内这些细胞因子的强烈且局部的免疫荧光相对应。在同一初始时间段内，VEGF 的 mRNA 上调主要发生在神经视网膜内，这种表达与紧邻损伤部位的 Müller 细胞的强烈免疫标记相对应。激光照射后 3 天，可测量到 VEGF(164) 蛋白表达增加，而早期新生血管发育在组织学上与 HGF 和 bFGF mRNA 扩展到正在形成的脉络膜新生血管膜（CNVM）相对应。在 7 天时，CNV 扩展、成熟以及血管通透性增加与 VEGF mRNA 和蛋白质的峰值表达以及 CNVM 的免疫荧光相对应。与视网膜相比，这些细胞因子的前体和活化异构体在视网膜色素上皮/脉络膜中的表达也存在差异。这些分子和免疫细胞化学结果表明，在这个 CNV 模型中，bFGF 和 HGF 可能作为新生血管形成的初始调节因子很重要；而 VEGF 可能在血管生成和新生血管高通透性的后期阶段很重要。
