小鼠嗅球以及吻侧迁移流的发生

Histogenesis of olfactory bulb and rostral migration stream in mice

目的：探讨嗅球结构和吻侧迁移流（RMS）的发生及其中神经干细胞的变化趋势。方法：利用H—E染色、Nissl染色标记嗅球形态结构，BrdU免疫荧光技术观察吻侧迁移流中增殖的神经干细胞。结果：嗅球组织结构的发生：胚胎期，嗅球各层的结构轮廓尚未发育完全；生后3d时，各层结构虽然发育完善，但层与层之间的交界处模糊不清，生后5d时，整个嗅球结构发育已经完善，也就意味着嗅觉系统发育成熟。迁移流的发生：胚胎初期，侧脑室是一个很大的空腔，管腔膜上布满了增殖的神经干细胞，脑室下区延伸人中空的嗅球中，之后管腔闭合，形成了原始的吻侧迁移流；出生时，吻侧迁移流中的细胞密度达到最大值，之后逐渐降低，直至消失。结论：嗅球片层化结构是从无到有，从不成熟到成熟的过程。吻侧迁移流的发生是侧脑室腔的闭合和室管下层上神经干细胞遗留的痕迹。

Objective： To discuss the structure of the olfactory bulb （OB）, the occurrence of the rostral migration streams （RMS） and the change trend of neural stem cells in RMS. Methods： The histological structure of the OB was marked by the methods of HE staining and Nissl staining. Using bromodeoxyuridine （BrdU）-immunofluorescence to observe the prolifera- tion of neural stem cells in RMS. Results： （Din the embryonic period, the outline of the structure of the OB layers was not fully developed yet. On the third day after birth the structure developed well, but the junctions between layers were blurred. In PS, the development of the entire olfactory bulb was improved. （2）In the early embryo, the lateral ventricle was a large cavity. The lumen membrance was full of the proliferation of neural stem cells. The subventricular zone extended into the hollow of OB, and then closed the lumen, forming the original rostral migration stream. In P0, the cell density in RMS reached its maximum value, then gradually reduced until it disappeared. Conclusion： The occurrence of OB tissue is the for- mation process of the structure. The occurrence of RMS is the event of both lateral ventricle elustion and remaining of neural stem cells.