大鼠室管膜下区和齿状回的EGFR表达

目的:探讨大鼠脑发育过程中表皮生长因子受体(EGFR)在室管膜下区(SVZ)和齿状回(DG)的表达及其意义。方法:选取正常不同发育时期SD大鼠脑,进行石蜡包埋连续切片,对大鼠脑室管膜、室管膜下区和海马DG进行EGFR免疫组织化学染色及光镜观察。应用免疫荧光双重染色观察EGFR和BrdU的共表达情况。结果:不同发育阶段大鼠的室管膜细胞都呈EGFR阳性。侧脑室背外侧角SVZ的EGFR阳性细胞在出生前及出生后早期较多,出生30d后(P30)EGFR阳性细胞数目锐减。在P7的SVZ,90%以上的EGFR细胞与BrdU共表达。在齿状回,颗粒细胞、一些位于SGZ、分子层和门区的细胞呈EGFR阳性。在大鼠胚胎晚期和出生后1周内,EGFR表达较高。P30,P120和P365,EGFR阳性细胞数较P7大幅度减少并且减少的主要是位于SGZ、分子层和门区的细胞。此外,在P7齿状回的各层可见一些EGFR阳性细胞表达BrdU。结论:EGFR在SVZ和DG有较强表达且表达随年龄增长有降低的趋势。在SVZ和DG各层可见EGFR和BrdU的细胞表达,EGFR信号途径在神经干(祖)细胞的增殖和特定类型神经元的分化及迁移过程中可能发挥重要作用。

EGFR expression in the subependymal zone and dentate gyrus of the Rats

Objective： To elucidate the expression and significance of epidermal growth factor receptor （EGFR） in the subventricular zone （SVZ） and dentate gyrus. Methods： The Sprague Dawley （SD） rats at different developmental stages were used. EGFR immunohistochemical staining and light microscope were performed in the paraffin-embedded serial brain sections including ependymal zone, subependymal zone and dentate gyrus of the hip- pocampus. Double immunofluorescence staining of BrdU and EGFR were observed. Results： The ependymal cells of the different developmental stages of rats were positive for EGFR. The number of EGFR-positive cells in SVZ of dorsolateral angle of the lateral ventricle in the prenatal and early postnatal rats was more than that afterwards and had a sharp drop after postnatal 7 days. In SVZ, 90% above BrdU cells co expressed EGFR at PT. In the dentate gyrus, EGFR positive cells were located in the granular layer, subgranular zone （SGZ） and molecular layer. EGFR expression had reached its peak at postnatal 5 days. The number of EGFR positive cells at P30, Plz0 and P36s signifi-cantly decreased compared with P7 and the reduced cells mainly located in SGZ, the molecular layer and hilus. In ad- dition, some EGFR-positive cells expressed BrdU in the different layers of the dentate gyrus at PT. Conclusion： EG- FR expressed strongly in SVZ and DG and the expression intensity decreased with age. Co expression of EGFR and BrdU cells could be detected in SVZ and DG, suggesting that they belong to different types of cells. EGFR signaling pathway in the proliferation of the neural stem / progenitor cell and differentiation of specific types of neurons and migration might play an important role.