Nogo-B在人脑胶质瘤中的表达及其与肿瘤病理分级的相关性

Nogo-B expression in human brain gliomas and its relationship with tumor pathological grades

目的:探讨Nogo-B基因在人脑胶质瘤组织中的表达及其与胶质瘤病理分级的相关性。方法:收集上海长征医院神经外科2005-2008年手术获得的经病理证实的人脑胶质瘤组织标本36份,另取其他手术切除的正常脑组织标本10份。以免疫组化技术、Real-time PCR和Western blotting等方法检测这些标本中Nogo-B在基因和蛋白质层面的表达水平,结合病理资料分析Nogo-B的表达和病理分级的相关性。结果:Real-time PCR检测发现,恶性程度高的胶质瘤组织中Nogo-B基因表达明显下调.Ⅲ级的胶质瘤组织中Nogo-B基因表达水平与正常脑组织相比下降了90%左右(P<0.01),Nogo-B基因表达水平与肿瘤的恶性度成相关。Western blotting检测显示,正常脑组织中Nogo-B蛋白表达相对恒定;在高恶性级别的胶质瘤中Nogo-B的蛋白表达显著下调,其下降程度与肿瘤的恶性程度呈负相关。免疫组织化学检测显示,Nogo-B主要在人正常脑组织中弥漫性阳性表达(100%),在人胶质瘤组织中表达显著降低;36例胶质瘤组织中Nogo-B染色阳性程度随着肿瘤恶性程度增加而显著降低(在Ⅰ-Ⅱ、Ⅲ、Ⅳ级中阳性表达分别为88.2%,42.9%,25.0%),各组间比较差异有统计学意义(P<0.01)。结论:在人脑胶质瘤中Nogo-B在mRNA和蛋白质水平上表达均出现下调,其下调程度与病理分级呈负相关。

Objective： To explore the expression of Nogo-B in brain gliomas and its relationship with the pathological grades of gliomas. Methods： The expression of Nogo-B was investigated in 10 normal brain tissues and 36 brain glioma specimens, which were confirmed after surgery during 2005-2008 in Changzheng Hospital, using immunohistoehemical method, real-time PCR and Western blotting assay. The relationship between Nogo-B expression and pathological grades were analyzed. Results： Tissue Nogo-B immunohistochemical staining in gliomas specimens suggested the involvement of Nogo-B in the proliferation of gliomas. The real-time PCR demonstrated that Nogo-B mRNA expression level in gliomas was obviously decreased in gliomas of high pathological grades, and the expression was stable in normal brain tissues. The expression of Nogo-B was negatively correlated with the malignancy of glioma. The expression in gliomas of grade Ⅲ decreased by 90% compared with the normal brain tissues （P 〈 0.01 ）. Western blotting showed that Nogo-B protein expres-sion was stable in normal brain tissues and obviously decreased in glioma tissues of high grade ; the decrease was negatively correlated with the malignancy of gliomas. Immunohistochemical analysis showed Nogo-B expression was scattered in the normal brain tissues （ 100% ） and greatly decreased in human gliomas. The expression of Nogo-B was decreased with the increase of the malignancy in our 36 specimens, being 88.2% ,42.9% ,and 25.0% in Ⅰ-Ⅱ,Ⅲ, and Ⅳ grades, respectively （P 〈0.01 ）. Conclusion： Nogo-B is decreases in human glioma at both protein and mRNA level. Nogo-B participats in the development and progression of bliomas, and its down-regulation is closely related to the malignancy of tumors.