Functional roles of astrocytes in modulating neural stem and progenitor cells in the adult mammalian spinal cord

成年哺乳动物脊髓缺乏自我修复能力，尽管脊髓内存在组织特异性神经干细胞(NSCs)。在发育过程中，神经干细胞显示出分化为包括神经元、星形胶质细胞和少突胶质细胞在内的所有类型脊髓细胞并构建脊髓的能力。然而，在成年脊髓中，神经干细胞的再生活性受到明显的限制。有趣的是，来自我们和其他研究人员的证据表明，成人脊髓损伤导致有限的少突胶质细胞替代，这是一种在脊髓神经纤维周围产生髓鞘所需的神经胶质细胞类型。这些发现强烈表明，存在严格调控成年脊髓内神经干细胞先天潜能的环境因素。

Adult mammalian spinal cord lacks the ability for self repair despite the presence of tissue-specific neural stem cells (NSCs) inside the spinal cord. During the developmental growth, NSCs show the capacity to give rise to all types of spinal cord cells including neurons, astrocytes and oligodendrocytes and build the spinal cord. However, in the adult spinal cord, the regenerative activity of NSCs is significantly restricted. Interestingly, evidence from our research and that of others demonstrates that injuries to the adult spinal cord result in limited oligodendroglial cell replacement, a glial cell type required for generating myelin sheath around the spinal cord nerve fibers. These findings strongly suggest the presence of environmental factors that tightly regulate the innate potential of NSCs within the adult spinal cord.