整合素α_5β_1在视网膜下膜中的表达

Expression of integrin α_5β_1 in subretinal membrane

目的研究整合素α5β1及其配体纤维粘连蛋白(FN)在视网膜中的表达。方法通过玻璃体切割术采集14例视网膜脱离病例的视网膜下膜标本,用免疫组织化学法检测下膜中角蛋白、整合素α5β1及FN的表达。免疫荧光双标记法研究视网膜下膜色素上皮细胞与整合素α5β1表达的关系,用激光扫描共聚焦显微镜定量分析视网膜下膜与正常视网膜下膜组织中整合素α5β1表达的差异。结果14例下膜标本中整合素α5β1和FN表达均呈阳性,免疫组织化学染色呈棕黄色,免疫荧光呈绿色或红色。角蛋白表达呈阳性的视网膜色素上皮(RPE)细胞的细胞膜上表达α5β1,见于下膜的全层;正常视网膜组织中α5β1的表达见于邻近Bruch膜的表面。两者比较差异有统计学意义(t=12.01、9.20,P<0.05)。结论在视网膜下膜组织中RPE细胞整合素α5β1表达上调,其配体FN也显著表达,表明整合素α5β1与FN参与了视网膜下膜的形成。

Objective Researches demonstrated that integrin α5β1 is expressed in epiretinal membrane and integrin α5β1 plays important role in the formation of proliferative vitreoretinopathy （PVR）. This study was to investigate the expressions of integrin α5β1 （VLA-5） and fibronectin（FN） in human subretinal membrane. Methods Subretinal membrane was collected from 14 patients with retina detachment during the vitrectomy,and 6 normal eyeballs from donor eyes were as control. The samples were detected with an avidin-biotin-complex （ABC） immunohistochemical technique using different antibodies specific for integrin α5, integrin β1, FN and keratin. Immunofluorescence histochemical double-staining technique was used to study the expression of integrin α5β1 in RPE cells and the quantitative analysis of intensity was taken by laser confocal microscope. Results Integrin α5β1, FN and CK were positively expreesed in subretinal membrane samples, showing buffy in immunohistochemistry and green or red staining in immunofluorescence. Throughout the subretinal membrane,the stronger integrin α5β1 expression was found on the cellular membrane of RPE with positive expression of keratin. The weak staining was detected at the surface of RPE cells near the Bruch membrane in the normal retina. A statistically significant difference was found in integrin α5β1 expression between subretinal membrane sample and normal sample （ t = 12.01,9.20,P 〈 0. 05 ）. Conclusion Integrin α5β1 and FN are over-expressed in subretinal membrane,implying integrin α5β1 may play an important role in the growth and pathogenesis of subretinal membrane.