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成年动物中枢神经系统中的NG2细胞具有异质性。脊髓损伤(SCI)后,具有少突胶质前体细胞(OPCs)功能的NG2细胞亚型如何产生反应性变化及对其正常的发育过程有何影响目前还不清楚。本文采用少突胶质细胞系细胞表达EGFP的CNP-EGFP小鼠,研究正常和SCI后的NG2细胞的特征。在正常小鼠的白质中,对EGFP+NG2+双极细胞和EGFPnegNG2+多极细胞进行鉴别。SCI后,白质损伤边缘区中的EGFP+NG2+细胞3 d增殖达高峰,损伤中心区的EGFPnegNG2+细胞增殖在损伤后7 d达高峰。损伤后EGFP+NG2+细胞的Olig2、Sox10、Sox17等转录因子、基本的膜电生理参数以及钾电流表型均与发育过程增殖的OPCs一致。EGFPnegNG2+细胞不表达少突胶质发生中的转录因子。EGFP+CC1+少突胶质细胞6周时包含在EGFP+NG2+细胞增殖峰时表达BrdU的细胞。EGFPnegCC1+少突胶质细胞未被观察到。神经胶质生长因子2和成纤维细胞生长因子2处理促进少突胶质发生,提高EGFPnegNG2+细胞数量。因此,通过EGFP和转录因子表达,时空增殖类型及对生长因子的反应,两种类型的NG2+细胞对SCI刺激发生反应。SCI后EGFP+NG2+细胞经受细胞和生理变化特征,与在早期出生后的少突胶质发生过程中NG2+细胞中的变化类似。
NG2 cells in the adult animal central nervous system are heterogeneous. It is unclear how the subpopulation of NG2 cells with oligodendrocyte precursor cells (OPCs) produce reactivity changes and their normal development after spinal cord injury (SCI). In this paper, CNP-EGFP mice expressing EGFP in oligodendrocyte lineage cells were used to study the characteristics of NG2 cells after normal and SCI. In normal white matter of mice, EGFP + NG2 + bipolar cells and EGFPnegNG2 + multipolar cells were identified. After SCI, the proliferation of EGFP + NG2 + cells in the marginal zone of white matter reached a peak at 3 days, and the proliferation of EGFPnegNG2 + cells reached the peak on the 7th day after SCI. Olig2, Sox10, Sox17 and other transcription factors, basic membrane electrophysiological parameters and potassium current phenotype of EGFP + NG2 + cells were consistent with those of proliferating OPCs. EGFPnegNG2 + cells do not express transcription factors in oligodendrocyte development. EGFP + CC1 + oligodendrocytes at 6 weeks contained BrdU-expressing cells at the proliferative peak of EGFP + NG2 + cells. EGFPnegCC1 + oligodendrocytes were not observed. Treatment with glial growth factor 2 and fibroblast growth factor 2 promoted oligodendrocyte formation and increased the number of EGFPnegNG2 + cells. Thus, both types of NG2 + cells respond to SCI stimulation through EGFP and transcription factor expression, types of space-time proliferation, and responses to growth factors. The EGFP + NG2 + cells underwent SCI after being characterized by both cellular and physiological changes similar to those in NG2 + cells during early oligodendrocyte development.