Department of Ophthalmology and Visual Science, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Am J Pathol. 2013 Jun;182(6):2147-54. doi: 10.1016/j.ajpath.2013.02.009. Epub 2013 May 15.
Subconjunctival fibrosis at the surgical site determines the outcome of glaucoma surgery. Myofibroblast transformation has a significant role in fibrosis, and vascular endothelial growth factor (VEGF) is reported to trigger myofibroblast transformation by inducing transforming growth factor (TGF)-β1. In the present study, we used IHC, Western blot analysis, enzyme-linked immunosorbent assay, and electron microscopy to determine the contribution of VEGF to myofibroblast transformation in subconjunctival fibrosis after glaucoma surgery. A rabbit trabeculectomy model was generated, and VEGF stimulation or VEGF inhibition was performed during surgery. VEGF stimulation induced TGF-β1 expression in a dose-dependent manner. Down-regulation of epithelial markers (E-cadherin and β-catenin) and up-regulation of mesenchymal marker (α-smooth muscle actin) were observed in the subconjunctival layers after trabeculectomy with VEGF stimulation. Up-regulations of Smad and Snail, which play a central role in myofibroblast transformation, were observed in the conjunctival and subconjunctival layers at the site of trabeculectomy. Electron microscopy revealed changes of the conjunctival epithelial cells, especially the presence of myofilaments and increased rough endoplasmic reticulum in the cytoplasm. Myofibroblast transformation was activated by VEGF stimulation and decreased by VEGF inhibition. These findings suggest that VEGF potentially affected the TGF-β1/Smad/Snail pathway, thereby triggering myofibroblast transformation. Therapeutic approaches modulating VEGF may control myofibroblast transformation and reduce subconjunctival fibrosis after glaucoma surgery.
手术部位的结膜下纤维化决定了青光眼手术的结果。成肌纤维细胞转化在纤维化中起重要作用，血管内皮生长因子（VEGF）通过诱导转化生长因子（TGF）-β1 被报道触发成肌纤维细胞转化。在本研究中，我们使用免疫组化、Western blot 分析、酶联免疫吸附试验和电子显微镜来确定 VEGF 在青光眼手术后结膜下纤维化中成肌纤维细胞转化中的作用。建立了兔小梁切除术模型，并在手术过程中进行 VEGF 刺激或 VEGF 抑制。VEGF 刺激以剂量依赖性方式诱导 TGF-β1 表达。在小梁切除术后，结膜下各层中观察到上皮标志物（E-钙粘蛋白和β-连环蛋白）下调和间充质标志物（α-平滑肌肌动蛋白）上调。在小梁切除部位的结膜和结膜下各层中观察到在成肌纤维细胞转化中起核心作用的 Smad 和 Snail 的上调。电子显微镜显示结膜上皮细胞发生变化，特别是细胞质中出现肌丝和增加的粗面内质网。VEGF 刺激激活成肌纤维细胞转化，而 VEGF 抑制则减少成肌纤维细胞转化。这些发现表明 VEGF 可能影响 TGF-β1/Smad/Snail 通路，从而触发成肌纤维细胞转化。调节 VEGF 的治疗方法可能控制青光眼手术后的成肌纤维细胞转化并减少结膜下纤维化。
