Dijkstra S, Bär P R, Gispen W H, Joosten E A
Department of Experimental Neurology, Rudolf Magnus Institute for Neurosciences, Utrecht University, The Netherlands.
Neuroscience. 1999;92(4):1331-42. doi: 10.1016/s0306-4522(99)00060-3.
Corticospinal neurons were identified in primary cultures of cortical neurons established from rats that had been injected with a fluorescent tracer to retrogradely label the corticospinal tract. We measured neurite outgrowth from corticospinal neurons after they had been co-cultured with astrocytes derived from either the cerebral cortex (homotopic region) or spinal cord (target region) of postnatal rats. The axon length of corticospinal neurons was increased when they were cultured on astroglial monolayers compared to a control monolayer (fibroblasts). However, no difference in axon length was noted on cortical versus spinal cord-derived astrocytes. On the other hand, total dendritic length was increased on cortical compared to spinal cord astrocytes. This increase in total dendrite length was not the result of differences in the length of primary dendrites, but primarily of a higher number of dendrites and increased branching on the cortical astroglia. If the corticospinal neurons were co-cultured without physical contact with the astrocytes, axonal and dendritic outgrowth were not stimulated when compared to the fibroblast control. The data indicate that dendritic growth from corticospinal neurons is preferentially promoted by astrocytes from the cerebral cortex, whereas axonal growth is not influenced by the anatomical origin of the astrocytes. The impact of these findings on our understanding of the role of astrocytes in the development and regeneration of the corticospinal tract is discussed.
在从注射了荧光示踪剂以逆行标记皮质脊髓束的大鼠建立的皮质神经元原代培养物中鉴定出皮质脊髓神经元。我们测量了皮质脊髓神经元与源自新生大鼠大脑皮质（同位区域）或脊髓（靶区域）的星形胶质细胞共培养后的神经突生长情况。与对照单层（成纤维细胞）相比，当皮质脊髓神经元在星形胶质细胞单层上培养时，其轴突长度增加。然而，在源自大脑皮质与脊髓的星形胶质细胞上，轴突长度没有差异。另一方面，与脊髓星形胶质细胞相比，在大脑皮质星形胶质细胞上总的树突长度增加。总的树突长度的增加不是初级树突长度差异的结果，而是主要由于大脑皮质星形胶质细胞上树突数量更多且分支增加。如果皮质脊髓神经元与星形胶质细胞不进行物理接触而共培养，与成纤维细胞对照相比，轴突和树突的生长不会受到刺激。数据表明，大脑皮质的星形胶质细胞优先促进皮质脊髓神经元的树突生长，而轴突生长不受星形胶质细胞解剖学来源的影响。本文讨论了这些发现对我们理解星形胶质细胞在皮质脊髓束发育和再生中作用的影响。
