Zhang N L, Samadani E E, Frank R N
Kresge Eye Institute of Wayne State University School of Medicine, Detroit, Michigan.
Invest Ophthalmol Vis Sci. 1993 Jul;34(8):2412-24.
Polypeptide growth factors, such as the acidic and basic fibroblast growth factors (aFGF and bFGF), may be important in the pathogenesis of subretinal neovascularization. The authors studied the relationship of aFGF and bFGF expression to retinal pigment epithelial (RPE) cell and choriocapillary endothelial cell proliferation in krypton-laser-treated regions of the retina, RPE, and choroid of a model of subretinal neovascularization in the pigmented rat they developed.
Multiple krypton laser burns were applied to the posterior poles of the eyes of pigmented rats according to a protocol described for producing subretinal neovascularization in these animals. At intervals up to 80 days after treatment, the retinas, RPE, and choroid of these animals were examined by [3H]-thymidine autoradiography and electron microscopic immunocytochemistry, using antibodies to aFGF, bFGF, cytoplasmic retinaldehyde-binding protein, opsin, and various basement membrane macromolecules.
Nuclear radiolabeling became evident in these layers when the label was injected as late as 75 days after photocoagulation, but the number of labeled nuclei was greatest when isotope was injected 2-5 days after laser treatment. Although there were labeled nuclei in the retina, RPE, and choroid, the frequency of labeling as a fraction of the total number of nuclei appeared to be greatest in the RPE and choriocapillaris. Non-laser-damaged RPE cells were immunocytochemically strongly positive for cytoplasmic retinaldehyde-binding protein, but were negative for aFGF and bFGF. After laser treatment, many RPE cells lost their cytoplasmic retinaldehyde-binding protein positivity but stained strongly for aFGF and bFGF within intracellular structures of variable shape and homogeneous appearance. Although these structures had an appearance suggestive of basement membrane, they did not stain with antibodies to collagens type IV or V, to laminin, or to heparan sulfate proteoglycan core protein. They also did not stain with an antibody to the N-terminal peptide of opsin. Choriocapillary endothelial cells were unreactive with antibodies to aFGF, bFGF, or cytoplasmic retinaldehyde-binding protein either before or after laser treatment. FGF-positive RPE cells persisted for the 80-day duration of the experiment.
Because the presence of FGF-positive RPE cells coincides temporally with increased nuclear thymidine labeling in the RPE and choriocapillaris, aFGF and/or bFGF may be at least partly responsible for initiating the process of cell proliferation and subretinal neovascularization in these animals.
诸如酸性和碱性成纤维细胞生长因子（aFGF和bFGF）等多肽生长因子可能在视网膜下新生血管形成的发病机制中起重要作用。作者在他们建立的色素大鼠视网膜下新生血管形成模型中，研究了aFGF和bFGF表达与视网膜色素上皮（RPE）细胞和脉络膜毛细血管内皮细胞在氪激光治疗的视网膜、RPE和脉络膜区域增殖之间的关系。
根据描述的在这些动物中产生视网膜下新生血管形成的方案，对色素大鼠的眼后极进行多次氪激光烧灼。在治疗后长达80天的间隔时间内，使用针对aFGF、bFGF、细胞质视黄醛结合蛋白、视蛋白和各种基底膜大分子的抗体，通过[3H] - 胸腺嘧啶核苷放射自显影和电子显微镜免疫细胞化学检查这些动物的视网膜、RPE和脉络膜。
当在光凝后长达75天注射标记物时，这些层中的核放射性标记变得明显，但当在激光治疗后2 - 5天注射同位素时，标记核的数量最多。尽管在视网膜、RPE和脉络膜中有标记核，但作为核总数一部分的标记频率在RPE和脉络膜毛细血管中似乎最高。未受激光损伤的RPE细胞对细胞质视黄醛结合蛋白免疫细胞化学呈强阳性，但对aFGF和bFGF呈阴性。激光治疗后，许多RPE细胞失去了细胞质视黄醛结合蛋白阳性，但在形状可变且外观均匀的细胞内结构中对aFGF和bFGF染色强烈。尽管这些结构外观提示基底膜，但它们对IV型或V型胶原、层粘连蛋白或硫酸乙酰肝素蛋白聚糖核心蛋白的抗体不染色。它们对视蛋白N端肽的抗体也不染色。脉络膜毛细血管内皮细胞在激光治疗前后对aFGF、bFGF或细胞质视黄醛结合蛋白的抗体均无反应。FGF阳性RPE细胞在实验的80天期间持续存在。
由于FGF阳性RPE细胞的存在在时间上与RPE和脉络膜毛细血管中核胸腺嘧啶核苷标记增加相吻合，aFGF和/或bFGF可能至少部分负责启动这些动物中的细胞增殖和视网膜下新生血管形成过程。
