胎儿侧脑室室管膜发育的免疫组织化学和电镜研究

Development of ependyma in brain of human fetus: an immunohistochemical and electron microscopic study

目的 :探讨胎儿脑发育过程中出现的放射状胶质细胞、伸展细胞和普通室管膜细胞之间的关系。方法 :运用HE染色、免疫组化染色和电镜观察胎儿侧脑室室管膜组织。结果 :1 2w时可见放射状胶质细胞和位于室管膜层的神经干细胞样细胞。少数放射状胶质细胞有单纤毛 ;2 0w时室管膜胶质纤维酸性蛋白 (GFAP)呈阳性 ,伸展细胞出现在室管膜层 ;2 8w大量GFAP阳性的星状胶质细胞位于室管膜下层和中间层 ;以后GFAP阳性强度和细胞数开始下降。 3 9w时GFAP阴性 ,无法见到伸展细胞。结论 :放射状胶质细胞主要转变为星状胶质细胞 ,少量转化为普通的室管膜细胞。伸展细胞可能来源于神经干细胞 ,部份转化为普通室管膜细胞 ;部分可能转化为其他细胞 ,可能是室管膜瘤中伸展细胞的来源。

Objective: To explore the relationship of radial glial cells, tanycytes and common ependymal cells appearing in human fetal brain. Methods: HE staining, GFAP immunohistochemistry, transmission electron microscopic techniques were applied to study the ependyma of lateral ventricle of human fetal brains. Results: Radial grail cells and some stem cell-like cells allocated at ependymal layer were detected under transmission electron microscope at 12th week. A few radial glial cells had single piece of cilium. GFAP positive emerged at the surface of ependyma and tanycytes bearing short and rough processes were found in the ependymal layer at 20th week. In 28th week, large quantities of GFAP positive astrocytes were present in subventricular and intermediate zone. After 28 th week the quantity of GFAP positive cells and the level of immunoreactivity declined. There were only a few GFAP positive cells on the surface of epndyma at 33th week. No GFAP positive cells or tanycytes were found at 39th week. Conclusion: Radial glial cells mainly differentiated into astrocytes and a few into common ependymal cells. Tanycytes might come from neural stem cell-like cells, part of them changed into common ependymal cells and the others might changed into other type of cells, which might be the source of the tanycytes which were present in ependymoma.