大鼠脊髓发育过程中神经干细胞的分化

Differentiation of neural stem cells during normal development of rat spinal cord

目的:研究正常大鼠脊髓发育过程中神经干细胞的分化规律。方法:应用免疫荧光染色技术,检测Nestin、NeuN、MAP2、GFAP、CNPase阳性细胞在大鼠胚胎期及生后脊髓内的分布及变化情况。结果:胚胎发育早期,脊髓中央管、灰质、白质均可检测到Nestin阳性细胞,生后Nestin阳性细胞数量逐渐减少。大鼠脊髓神经元的发生呈现明显的背腹模式,孕14d(E14)脊髓内可检测到NeuN阳性细胞,E16 NeuN阳性细胞逐渐增多,腹侧NeuN阳性细胞核体积较大,分布较稀疏,背侧神经元细胞核体积较小,分布较密集。MAP2染色结果与NeuN一致。胶质细胞的分化、成熟在生后初期进行,P4可检测到GFAP及CNPase阳性细胞,主要分布于脊髓白质内,P30在脊髓灰质内可检测到GFAP阳性细胞,细胞分支较多且短。结论:正常大鼠脊髓发育中神经干细胞的分化呈现一定规律性,向神经元方向化较早且呈明显的背腹模式,胶质细胞的分化较晚。

Objective： To detect the pattern of cell proliferation and differentiation during the normal development of rat spinal cord. Methods： The distribution of Nestin, NeuN, MAP2, GFAP, CNPase positive cells in the rat spinal cord during both embryonic and postnatal stage was detected by using immunofluorescent technology. Results： In the early stage of embryo, Nestin positive cells were detected in central canal, gray matter and white matter and decreased in number after birth. The neurogenesis was presented as dorsal-ventral patterning, and originated at E14. Lots of NeuN positive cells were detected at E16. The MAP2 labeling was consistent with that of NeuN. The positive nucleus in ventral side were larger and more sparse, whereas the positive nucleus in dorsal side were smaller and denser. Gliogenesis and maturation advanced quickly at the early stage after birth. GFAP and CNPase positive cells were detected in white matter at P4. At P30, GFAP positive cells were still detected in gray matter, in which branches were more and shorter. Conclusion： The proliferation and differentiation of NSCs have some regularity during the development of the rat spinal cord. The onest of neurogenesis is early, and neurogenesis has obviously dorsal-ventral （D-V） pattern. The differentiation of glial cells advances quickly at the early stages after birth.