Dreyfus C F, Dai X, Lercher L D, Racey B R, Friedman W J, Black I B
Department of Neuroscience and Cell Biology, UMDNJ/Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
J Neurosci Res. 1999 Apr 1;56(1):1-7. doi: 10.1002/(SICI)1097-4547(19990401)56:1<1::AID-JNR1>3.0.CO;2-3.
Potential roles of trophins in the normal and injured spinal cord are largely undefined. However, a number of recent studies suggest that adult spinal cord expresses neurotrophin receptors and responds to the neurotrophins, brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT3), particularly after injury. The data indicate that trophins may enhance regrowth after damage and may represent a new therapeutic approach to injury. Neurotrophins are reportedly present in the spinal cord, but the cellular localization is unknown. This information is critical to begin delineating mechanisms of actions. To approach this problem, we examined whether spinal cord glia express BDNF and NT3 in vivo and have begun to define cellular distribution. Specific antibodies directed against the neurotrophins were utilized to visualize neurotrophin protein. Initial studies indicated that small cells in the white matter of adult rat spinal cord express BDNF and NT3. Large neurotrophin-positive neurons were also identified in the ventral cord. To identify the neurotrophin-positive cells, co-localization studies were performed utilizing neurotrophin polyclonal antisera together with monoclonal antibodies directed against the astrocyte marker, glial fibrillary acidic protein (GFAP). In the white matter of adult spinal cord, GFAP-positive and GFAP-negative cells expressed BDNF and NT3. Our study suggests that astrocyte and non-astrocyte cells provide trophic support to the adult spinal cord.
神经营养因子在正常及损伤脊髓中的潜在作用在很大程度上尚不明确。然而，最近的一些研究表明，成年脊髓表达神经营养因子受体，并对神经营养因子、脑源性神经营养因子（BDNF）和神经营养因子3（NT3）产生反应，尤其是在损伤后。数据表明，神经营养因子可能会促进损伤后的再生，并且可能代表一种新的损伤治疗方法。据报道，神经营养因子存在于脊髓中，但细胞定位尚不清楚。这些信息对于开始阐明其作用机制至关重要。为了解决这个问题，我们研究了脊髓胶质细胞在体内是否表达BDNF和NT3，并已开始确定细胞分布。利用针对神经营养因子的特异性抗体来可视化神经营养因子蛋白。初步研究表明，成年大鼠脊髓白质中的小细胞表达BDNF和NT3。在腹侧脊髓中也发现了大型神经营养因子阳性神经元。为了鉴定神经营养因子阳性细胞，利用神经营养因子多克隆抗血清与针对星形胶质细胞标志物胶质纤维酸性蛋白（GFAP）的单克隆抗体进行共定位研究。在成年脊髓白质中，GFAP阳性和GFAP阴性细胞均表达BDNF和NT3。我们的研究表明，星形胶质细胞和非星形胶质细胞为成年脊髓提供营养支持。
