神经导向因子 1 可同时抑制角膜炎症和血管新生。

Netrin-1 simultaneously suppresses corneal inflammation and neovascularization.

机构信息

Eye Institute of Xiamen University, Xiamen, Fujian, China.

出版信息

Invest Ophthalmol Vis Sci. 2012 Mar 9;53(3):1285-95. doi: 10.1167/iovs.11-8722.

DOI:10.1167/iovs.11-8722

PMID:22323486

Abstract

PURPOSE

To investigate the effect of netrin-1 on alkali burn-induced corneal inflammation and neovascularization.

METHODS

The expression of netrin-1 and its receptors UNC5A, UNC5B, UNC5C, UNC5D, adenosine 2b receptor (A2BAR), deleted in colorectal cancer (DCC), and neogenin in normal and alkali-burned rat cornea were determined by RT-PCR and/or Western blot analysis, or immunostaining. Topical netrin-1 protein was applied to treat rat corneal alkali-burn injury for 14 consecutive days, started right after the injury or 10 days postinjury. Corneal inflammation and neovascularization were observed under slit lamp microscope. The apoptosis of corneal cells was determined by terminal deoxynucleotidyl transferase-mediated nick end labeling assay. Corneal inflammatory cell infiltration was evaluated by immunostaining of anti-PMN and anti-ED1 antibodies. The expression of epidermal growth factor (EGF), vascular epidermal growth factor (VEGF), and pigment epithelium-derived factor (PEDF) in rat cornea was determined by Western blot analysis.

RESULTS

Netrin-1 and its receptor UNC5B were expressed in normal rat corneal epithelium and stromal cells, and their expression decreased after corneal alkali burn. Exogenous netrin-1 administered on rat ocular surfaces resolved alkali burn-induced corneal inflammation, and also suppressed corneal neovascularization. Furthermore, netrin-1 could reverse neovascularization in alkali-burned cornea. The authors found that netrin-1 executed the functions through various mechanisms, including upregulating EGF expression, accelerating epithelial wound healing, inhibiting neutrophil and macrophage infiltration, reducing corneal cell apoptosis, and restoring the equilibrium of VEGF and PEDF in the wounded cornea.

CONCLUSIONS

Netrin-1 could dampen inflammation, inhibit, and reverse neovascularization in alkali-burned cornea.

摘要

目的

研究轴突导向因子 netrin-1 对碱烧伤诱导的角膜炎症和新生血管形成的影响。

方法

采用 RT-PCR 和/或 Western blot 分析或免疫染色法检测正常和碱烧伤大鼠角膜中 netrin-1 及其受体 UNC5A、UNC5B、UNC5C、UNC5D、腺苷 2b 受体（A2BAR）、结直肠癌缺失基因（DCC）和 neogenin 的表达。在碱烧伤后立即或 10 天开始，连续 14 天用 netrin-1 蛋白局部处理大鼠角膜碱烧伤。用裂隙灯显微镜观察角膜炎症和新生血管形成。用末端脱氧核苷酸转移酶介导的缺口末端标记法测定角膜细胞凋亡。用抗多形核白细胞（PMN）和抗 ED1 抗体的免疫染色评估角膜炎性细胞浸润。用 Western blot 分析测定大鼠角膜中表皮生长因子（EGF）、血管内皮生长因子（VEGF）和色素上皮衍生因子（PEDF）的表达。

结果

netrin-1 和其受体 UNC5B 在正常大鼠角膜上皮细胞和基质细胞中表达，碱烧伤后表达降低。眼表面给予外源性 netrin-1 可缓解碱烧伤引起的角膜炎症，并抑制角膜新生血管形成。此外，netrin-1 可逆转碱烧伤后的新生血管形成。作者发现 netrin-1 通过多种机制发挥作用，包括上调 EGF 表达、加速上皮愈合、抑制中性粒细胞和巨噬细胞浸润、减少角膜细胞凋亡、恢复受损角膜中 VEGF 和 PEDF 的平衡。