脑肿瘤干细胞的增殖活性与微血管密度的相关性研究

The Study of the Relation between Proliferating Brain Tumor Stem Cells with Micro-vascular System

背景与目的:越来越多的研究表明脑肿瘤干细胞(brain tumor stem cell,BTSC)起源于神经干细胞(neural stem sell,NSC)的基因突变。本研究检测脑肿瘤干细胞标志物CD133、增殖细胞核标志物Ki-67和血管内皮细胞标志物CD31在68例脑胶质瘤中的表达,探讨脑肿瘤干细胞的增殖活性与微血管密度的相关性。方法:(1)采用免疫组织化学SP法检测CD133、Ki-67和CD31在68例胶质瘤组织中的表达。(2)采用免疫荧光双染法检测CD133/Ki-67和CD133/CD31的共表达情况。计算CD133^+肿瘤干细胞、CD31^+血管和Ki-67^+细胞所占的百分率,并进行统计学分析。结果:按照WHO2000年的神经系统肿瘤分类分级标准所有标本分为Ⅱ级23例,Ⅲ级19例,Ⅳ级26例。CD133^+肿瘤干细胞、CD31^+血管和Ki-67^+细胞在各级别胶质瘤中均有表达,在低级别组中,免疫组化中可见CD133^+肿瘤干细胞、CD31^+血管和Ki-67^+细胞较少,免疫荧光双染可见CD133^+/Ki-67^+肿瘤干细胞较少,CD133^+肿瘤干细胞周围的CD31^+血管散在分布,同时可见少数CD133^+/CD31^+血管。而在高级别组中,免疫组化中CD133^+肿瘤干细胞、CD31^+血管和Ki-67^+细胞数明显增加,荧光双染中CD133^+/Ki-67^+细胞和CD133^+肿瘤干细胞周围的CD31+血管均明显增多,同样可见少数CD133^+/CD31^+血管。并且,Ki-67^+细胞(r=0.758,P<0.001)和CD31+血管(r=0.439,P<0.001)在高低级别组中的表达均与CD133^+肿瘤干细胞的表达呈正相关,并且,Ki-67^+细胞和CD31^+血管之间也呈明显的正相关(r=0.816,P<0.001)。结论:在脑胶质瘤组织中,脑肿瘤干细胞的增殖活性与微血管是密切联系的,不仅表现在区域分布上肿瘤干细胞围绕微血管增殖分化,还可以表现在功能上与微血管的相互促进和相互依赖。

BACKGROUND OBJECTIVE：Brain tumor stem cells（BTSCs） has been considered as the origin and the progression of gliomas and angiogenesis is a significant characteristic of gliomas.The aim of the present study was to investigate the expressions of the putative brain tumour stem cells marker CD133,proliferating cell nuclear marker Ki-67 and blood vessel endothelial cell marker CD31 in 68 cases of formalin fixed paraffin embedded gliomas.The relationship of the BTSCs distribution with micro-blood vessels was analyzed using morphometry.METHODS：（1） The expression levels of Ki67,CD31 and CD133 protein were detected using SABC immunohistochemical analysis.Percentage of the CD133~＋ cells、CD31~＋ blood vessels and Ki-67~＋ cells was calculated.（2） Double immunofluorescence staining was used to detect the co-expressions of CD133/CD31 and CD133/Ki-67 in tissue samples.Then,the correlation of the proliferating brain tumor stem cells with microvascular system was determined.RESULTS：（1） Among 68 tumors,23 were grade Ⅱ,19 were grade Ⅲ and 26 were grade Ⅳ,according to WHO 2000 classification of nervous system tumors.CD31~＋ blood vessels,CD133~＋ cells and Ki67~＋ cells were observed in all glioma tissues.In low-grade group,there were fewer CD31~＋ blood vessels,CD133~＋ cells and Ki-67~＋ cells compared with those in high-grade group.The CD133~＋/CD31~＋ cells were found co-expressed in the endothelial cells by using double immunofluorescence staining both in low-and high-grade group.Positive correlation was observed between the Ki-67~＋ cells（r = 0.758,P 0.001）or CD31＋ blood vessels（r = 0.439,P 0.001）with CD133~＋ cells.And the positive correlation was also observed between the Ki-67~＋ cells with CD31~＋ blood vessels（r = 0.816,P 0.001）.CONCLUSION：In gliomas,the proliferating BTSCs and micro-vascular system are close related to each other not only in the regional distribution but also in biological function.