脑肿瘤血脑屏障形态学改变与脑肿瘤转移关系的探讨

The BBB Morphology Features of Brain Tumor

目的 探索脑肿瘤的血道转移发生机制。方法 应用透射电镜技术及免疫组化技术对脑肿瘤毛细血管超微结构水平及免疫组化水平的结构改变进行比较观察。结果 超微结构观察发现 ,胶质瘤中微血管基膜连续 ,完整 ,厚薄不均匀 ,有分层 (层内夹有周细胞 ) ,与正常脑组织血管基膜无异。转移瘤中基膜不清晰 ,不连续 ,纤细疏松 ,有典型窗孔结构。免疫组化结果显示Col lagenⅣ ,Fibronectin ,Laminin(CollⅣ ,FN ,LM ) 3种抗原在正常脑组织及脑瘤组织中的血管基膜和软脑膜均有表达 ,各型、各级胶质瘤血管基膜部分呈线状连续完整 ,部分呈分层网格状增厚。 3种基膜成分在转移瘤内及周边血管中均有不同程度表达 ,且基膜呈线状连续完整。结论 胶质瘤细胞虽有一定程度的异形性 ,但胶质瘤中的血脑屏障从形态学上未见异常 ,说明胶质瘤细胞具有诱导血脑屏障形成的特性。这可能是不发生颅外转移的原因之一。脑转移瘤的血管形态不具备有完整的血脑屏障的结构特征。

Objective To explore the metastatic possibility and mechanism of brain tumor through blood vessel.Methods The BBB(blood brain barrier) ultrastructure features in glioma and brain metastatic tumor were observed with electric transmission microscope.At the same time the collagen Ⅳ(CollⅣ),Fibronectin(FN),Laminin(LM) were detected in tumor tissue with immunohistochemistry staining.Results Three antigens(CollⅣ,FN,LM) staining were positive in the capilary basement membrane of brain tumor and the leptomeningeal.Most of basement membranes of microvessel were continued and lineal,some of them were multilayered and network like,some staining was weak.Under the transmission electron microscope,the BBB morphological differences of all kinds brain tumors were compared.In the capillary of glioma,the intact tight junction could be found,the basement membrane was continued,compact and clear,pericytes lie in the basement membrane,the fenestration on the basement membrane was not found.Capillary morphological difference had not been found between glioma tissue and normal brain tissue.In the metastatic tumor,the endothelium tight junctions were found.The basement membrane was thin,not clear and loose.The fenestration in the basement membrane was found.Special changes of BBB in glioma tissue were not found.Conclusion Although the glioma cell express some atypia,it still remains some characteristics to induce the formation of the BBB.Perhaps,this characteristics contributes to the obstacle of glioma cell metastasize to extracranial organs.The brain metastatic tumor does not preserve the integrity of BBB.