Mothe A J, Tator C H
Toronto Western Research Institute and Krembil Neuroscience Centre, McL 12-423, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8.
Neuroscience. 2005;131(1):177-87. doi: 10.1016/j.neuroscience.2004.10.011.
Ependymal cells of the adult mammalian spinal cord exhibit stem/progenitor cell properties following injury. In the present study, we utilized intraventricular injection of 1,1'-dioctadecyl-6,6'-di(4-sulfophenyl)-3,3,3',3'-tetramethylindocarbocyanine (DiI) to label the ependyma lining the central canal to allow tracking of the migration of endogenous ependymal cells and their progeny after spinal cord injury (SCI). We developed a minimal injury model that preserved the integrity of the central canal and did not interfere with ependymal cell labeling. Three days following SCI, there was an 8.6-fold increase in the proliferative labeling index of the ependymal cells at the level of the needle track based on bromodeoxyuridine labeling, compared with 1 day post-injury. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) positive cells were not detected in the ependyma or surrounding gray matter, indicating that ependymal cells do not undergo apoptosis in response to minimal injury. Nestin was rapidly induced in the ependyma by 1 day and expression peaked by 7 days post-injury. We quantitated the number and distance of ependymal cell migration following minimal injury. The number of ependymal cells migrating from the region of the central canal increased by 3 days following minimal injury and DiI-labeled glial fibrillary acidic protein expressing cells were detected 14 days post-SCI, most of which migrated within 70 microm of the region of the central canal. These results show that a minimal SCI adjacent to the ependyma is sufficient to induce an endogenous ependymal cell response where ependymal stem/progenitor cells proliferate and migrate from the region of the central canal, differentiating primarily into astrocytes.
成年哺乳动物脊髓的室管膜细胞在损伤后表现出干细胞/祖细胞特性。在本研究中，我们利用脑室内注射1,1'-二辛基-6,6'-二(4-磺基苯基)-3,3,3',3'-四甲基吲哚碳菁(DiI)来标记中央管内衬的室管膜，以便追踪脊髓损伤(SCI)后内源性室管膜细胞及其子代的迁移。我们建立了一个最小损伤模型，该模型保留了中央管的完整性，且不干扰室管膜细胞标记。与损伤后1天相比，SCI后3天，基于溴脱氧尿苷标记，针道水平的室管膜细胞增殖标记指数增加了8.6倍。在室管膜或周围灰质中未检测到末端脱氧核苷酸转移酶介导的dUTP缺口末端标记(TUNEL)阳性细胞，这表明室管膜细胞不会因最小损伤而发生凋亡。巢蛋白在损伤后1天在室管膜中迅速被诱导，7天时表达达到峰值。我们对最小损伤后室管膜细胞迁移的数量和距离进行了定量。最小损伤后3天，从中央管区域迁移的室管膜细胞数量增加，SCI后14天检测到DiI标记的表达胶质纤维酸性蛋白的细胞，其中大多数在中央管区域70微米范围内迁移。这些结果表明，与室管膜相邻的最小SCI足以诱导内源性室管膜细胞反应，室管膜干细胞/祖细胞从中央管区域增殖并迁移，主要分化为星形胶质细胞。
