诱导型一氧化氮合酶在大鼠脉络膜新生血管中的表达及其与血管生成的关系

Expression of iNOS and its relationship with choroidal neovascularization induced by krypton laser in BN rat

目的探讨氪激光诱导大鼠脉络膜新生血管(choroidal neovascularization,CNV)形成中诱导型一氧化氮合酶(inducible nitric oxide synthase,i NOS)和血管内皮生长因子(vessel endothelial growth factor,VEGF)的表达及其与CNV形成的关系。方法对5组30只BN大鼠行单眼视网膜氪激光光凝,诱导脉络膜新生血管形成。分别在光凝后3d、1周、2周、3周、4周摘除眼球,应用免疫组织化学技术对光凝区进行Ⅷ因子相关抗原(factorⅧrelated antigen,FⅧR:Ag)检测以观测CNV形成,并检测CNV形成过程中i NOS、VEGF蛋白的表达,半定量分析i NOS、VEGF表达变化与CNV生成的相关性。结果FⅧR:Ag免疫组织化学检查结果显示,光凝后1周开始形成CNV,3~4周达到高峰。正常BN大鼠视网膜中,i NOS在神经节细胞、内核层表达;VEGF在视网膜神经节细胞层、内核层、色素上皮层、视网膜和脉络膜血管内皮细胞均有表达。视网膜光凝后,除上述部位外,i NOS和VEGF均在外核层和脉络膜的光凝损伤区阳性表达。光凝后3d^4周,光斑区内FⅧR:Ag、i NOS和VEGF阳性染色密度逐渐增加(P<0.05);i NOS、VEGF与FⅧR:Ag阳性染色密度正相关(r=0.89,r=0.78,P<0.05);i NOS与VEGF阳性染色密度正相关(r=0.78,P<0.05)。结论i NOS与VEGF同步表达,其阳性表达密度与CNV生成正相关,i NOS在CNV生成中可能起着重要的作用。

Objective To study the expression of inducible nitric oxide synthase（iNOS） and vessel endothelial growth factor（VEGF） in choroidal neo vascularization （CNV）,and to investigate their relationship with CNV induced by krypton laser in BN rat. Methods Five groups of 30 BN rats were photocoagulated by krypton laser in single eye. Three days, 1 week, 2 weeks, 3 weeks and 4 weeks after photocoagulation, the expression of iNOS, VEGF and F Ⅷ R： Ag was observed by immunohistochemical method, and their expression was analyzed semi-quantitatively. Results Factor Ⅷ related antigen（F Ⅷ R： Ag） positive staining cells formed vessels in the lesions 1 week after photocoagulation, and gradually increased until 3- 4 weeks, iNOS expressed in the ganglion cells and inner nuclear layer in normal BN retina. After photocoagulation, the expression of iNOS was also observed in the lesions of outer nuclear layer and choroid. VEGF expression was observed in the ganglion cells, inner nuclear layer, retinal pigment epithelial cells, the vascular endothelial cells in normal retina and choroid,and it also expressed in the lesions of outer nuclear layer and choroid after photocoagulation. From 3 days to 4 weeks, the expres- sion density of F Ⅷ R： Ag, iNOS and VEGF in the lesions gradually increased （ P 〈 0.05）. The expression of iNOS and VEGF was positive correlated with that of F Ⅷ R ： Ag（ r = 0.89, r = 0.78, P 〈 0.05 ）. The expression of iNOS was positively correlated with that of VEGF（r = 0.78, P 〈 0.05）. Conclusion The expression of iNOS and VEGF increase simultaneously in CNV and is positively correlated with CNV. iNOS may play an important role in the formation and development of CNV.