血管内皮钙黏蛋白对实验性角膜新生血管的作用及机制

目的 探讨血管内皮钙黏蛋白（VE-cadherin）在实验性角膜新生血管发生过程中的作用及机制。方法 动物实验研究。以碱烧伤诱导构建小鼠角膜新生血管模型；RT-PCR法检测VE-cadherin在碱烧伤角膜组织中的表达；碱烧伤1周后角膜局部应用阻断性抗小鼠VE-cadherin抗体进行干预，碱烧伤3周后大体观察角膜新生血管的发生情况以及全角膜铺片CD31荧光组织化学法检测角膜组织新生血管的面积；RT-PCR检测烧伤角膜组织内caspase-3 mRNA的表达；流式细胞术检测角膜组织血管内皮细胞凋亡数目；体外实验进一步验证VE-cadherin对血管内皮细胞（HREC）血管网形成的影响。采用成组t检验方法处理数据。结果 碱烧伤3周后，VE-cadherin抗体干预组角膜新生血管数目较对照组明显减少。RT-PCR结果显示VE-cadherin抗体干预组caspase-3基因水平表达增高；进一步流式细胞术检测结果显示VE-cadherin抗体干预后，角膜组织内凋亡的血管内皮细胞明显增多。体外实验证实VE-cadherin抗体明显抑制HREC细胞系血管网的形成。结论 VE-cadherin钙黏蛋白能通过维护细胞间黏附以及抑制细胞的凋亡等作用保护实验性角膜新生血管内皮细胞的生长，从而维持新生血管的发生发展。

The effect and mechanism of VE-cadherin on the development of experimental corneal neovascularization

Objective To explore the effect and mechanism of vascular endothelial cadherin （VE-cadherin） on the development of experimental corneal neovascularization. Methods This was an animal experimental study. Mouse corneas were burned by NaOH to induce corneal neovascularization. The gene expression of VE-cadherin in burned corneas was examined by RT-PCR. The neutralizing anti-VE-cadherin antibody was locally administrated 1 week after the alkali injury and the formation of corneal neovascularization was examined 3 weeks after the injury by corneal whole mount staining with CD31. The mRNA expression of caspase-3 in burned corneas was detected by RT-PCR and the number of apoptosis neovascular endothelial cells in corneas was examined by FCS （flow cytometry）. The effect of VE-cadherin on human retinal endothelial cells （HRECs） tube formation was detected in vitro. Data were analyzed statistically with a two-tailed Student′s t-test. Results Compared to the control group， the group treated with the neutralizing anti-VE-cadherin antibody showed significantly decreased corneal neovascularization. RT-PCR confirmed that neutralizing anti-VE-cadherin antibody treatment resulted in an increase of caspase-3 expression in corneal tissue. FCS revealed that antibody treatment resulted in increased intracorneal apoptosis neovascular endothelial cells. In addition， the tube formation ability of HRECs was found to be significantly inhibited by neutralizing antibody in vitro. Conclusion VE-cadherin plays vital roles in experimental corneal neovascularization by down-regulating caspase-3 mRNA expression， reducing the number of apoptic cells and promoting cell-cell adhesion.