Kirsch M, Schneider T, Lee M Y, Hofmann H D
Institute of Anatomy I, University of Freiburg, Germany.
Glia. 1998 Jul;23(3):239-48.
There is evidence that ciliary neurotrophic factor (CNTF) is involved in reactive changes following lesions of the nervous system. To investigate, whether differences in the regulation of CNTF and CNTF receptor alpha (CNTFRalpha) contribute to the differences in PNS and CNS responses to injury, we have studied their expression on the mRNA and protein level in the rat optic nerve following a crush lesion to compare them with the situation in peripheral nerve. Seven days after the lesion, CNTF mRNA and protein levels were markedly decreased at the lesion site, concommitant with the disappearance of GFAP- and CNTF-immunopositive astrocytes. CNTF levels in proximal and distal parts were less affected. This was in contrast to the situation in the PNS, where CNTF was downregulated at and distal to the lesion site. Different from other CNS regions, optic nerve astrocytes expressed CNTFRalpha mRNA under normal conditions. Following lesion, CNTFRalpha was reduced substantially only in distal and proximal parts of the optic nerve but continued to be expressed at high levels at the lesion site, suggesting that GFAP-negative, CNTF-responsive cells are present there. Our results suggest that differences in lesion-induced changes in the optic and sciatic nerve reflect differences in the response to injury of astrocytes and Schwann cells. In the light of the known actions of CNTF in inducing astrogliosis, the expression pattern observed in the optic nerve indicates that CNTF and CNTFRalpha are involved in glial scar formation in the lesion area.
有证据表明睫状神经营养因子（CNTF）参与神经系统损伤后的反应性变化。为了研究CNTF和CNTF受体α（CNTFRα）调节上的差异是否导致周围神经系统（PNS）和中枢神经系统（CNS）对损伤反应的差异，我们研究了挤压损伤后大鼠视神经中它们在mRNA和蛋白质水平上的表达，以便与周围神经的情况进行比较。损伤后7天，损伤部位的CNTF mRNA和蛋白质水平显著降低，同时GFAP和CNTF免疫阳性星形胶质细胞消失。近端和远端部分的CNTF水平受影响较小。这与PNS的情况相反，在PNS中，损伤部位及其远端的CNTF下调。与其他中枢神经系统区域不同，正常情况下视神经星形胶质细胞表达CNTFRα mRNA。损伤后，CNTFRα仅在视神经的远端和近端部分大幅减少，但在损伤部位仍持续高水平表达，这表明那里存在GFAP阴性、对CNTF有反应的细胞。我们的结果表明，视神经和坐骨神经损伤诱导变化的差异反映了星形胶质细胞和雪旺细胞对损伤反应的差异。鉴于CNTF在诱导星形胶质细胞增生方面的已知作用，在视神经中观察到的表达模式表明CNTF和CNTFRα参与损伤区域的胶质瘢痕形成。
