环氧合酶-2及其抑制剂对角膜新生血管作用的研究

Effect of COX-2 and its inhibitor Celcoxib on corneal neovascularization

目的观察大鼠角膜新生血管(CNV)形成过程中环氧合酶-2(COX-2)的表达,探讨COX-2抑制剂Celecoxib对CNV的作用。方法采用免疫组织化学方法、RT-PCR法检测碱烧伤后COX-2和VEGF蛋白、mRNA在角膜中的分布,比较实验组和对照组COX-2与VEGF蛋白和mRNA的表达量,计算二者的相关性。结果碱烧伤2d,CNV芽形成,4d出现成熟的新生血管腔。活化的COX-2、VEGF蛋白和mRNA的表达在碱烧伤24h开始增加,4d达峰,7d开始回落,14d仍有表达。COX-2主要表达于大鼠角膜损伤上皮及修复的上皮层、基质层中浸润的炎性细胞和新生血管内皮细胞,VEGF与COX-2的表达部位一致。实验Ⅱ组和Ⅲ组COX-2和VEGF蛋白、mRNA表达量与对照组的差异有统计学意义(P<0.05),实验Ⅰ组与对照组的差异无统计学意义(P>0.05)。结论COX-2在炎性CNV形成过程中表达上调,通过调控VEGF的表达而起重要作用。Celecoxib抑制COX-2的表达,抑制CNV形成。

Objective Corneal neovaseularization （CNV） is a erneial reason in inflammatory keratopathy inducing decreased vision and corneal graft rejection. Cyelooxygenase-2 （COX-2） is an important inducible enzyme in inflammation. The objective of this experiment was to investigate the relationship between CNV and COX-2 and to study the effects of eeleeoxib on eorneal neovaseularization. Methods The eorneal neovaseularization was induced by eorneal eautery with filtering paper soaked 1 mol/L NaOH in 80 Sprayue-Dawley（SD） rats. The rats were randomly divided into group Ⅰ , Ⅱ, Ⅲand eontrol group. 1 μmol/L,2 μmol/L and 3 μmol/L of Celeeoxib and saline solution were separately injected subeonjunetivally in group Ⅰ ,Ⅱ, Ⅲand control group after induction of neovaseularization. The expression of COX-2 and VEGF was examined by immunohistoehemistry and RT-PCR. Integration optic density （IOD） of COX-2 and vascular endothelial growth factor（VEGF） in cornea of rat were measured with eomputerized image analysis. Results The eorneal neovaseularization grew rapidly in 2-4 days after corneal eautery. The edema and inflammation of cornea were slighter in group Ⅱ in comparison with control group. The expressions of activated COX-2 and VEGF were significantly increased in 2-4 days after corneal eautery, showing a heavy brown staining mainly in epithelium, basement layer and neovaseular endothelium of cornea, and a gradually weaken tendency was seen 7 days later. There were weaker expression of COX-2 and VEGF in group Ⅱ, Ⅲcompared with control group （ P = 0. 008, P = 0. 007 ） , but no significant difference was found between group Ⅰ and control group（ P =0. 998 ）. There were positive eorrelations between COX-2 and VEGF in experimental and control group. Conclusion The activity of COX-2 is increased in the early stage of eorneal neovaseularization of SD rat. COX-2 plays an important role in the pathogenesis of eorneal neovaseularization by regulating VEGF. Topical application of Celeeoxib has signifieant effeets on the inhibition of activity of COX-2 and corneal anglogenesis.