Schinstine M, Cornbrooks C J
Department of Anatomy and Neurobiology, University of Vermont College of Medicine, Burlington 05405.
Exp Neurol. 1990 Apr;108(1):10-22. doi: 10.1016/0014-4886(90)90002-a.
Previous studies have suggested that embryonic (nonaxotomized) and regenerating central nervous system neurons differentially respond to the same substrata. In the present study, we have used an in vitro model to test the ability of laminin and type I collagen to promote the outgrowth of neurites from nonaxotomized and axotomized, embryonic septal-basal forebrain (SBF) neurons. Neurons within explants derived from Embryonic Day (E) 15 rats extended neurites that demonstrated similar growth characteristics on a collagen or laminin substratum. E15 neurons could be induced to extend longer neurites on laminin if they were axotomized in vitro and subsequently replated onto a laminin substratum. The carbocyanine dye DiI indicated that neurons which were axotomized could survive and regenerate processes. These regenerating neurites grew 27% longer on laminin than they did on collagen. Similarly, neurons that were axotomized in situ, i.e., E18 SBF neurons, extended neurites that were 29% longer on a laminin substratum. In contrast, E15 explants that were maintained in suspension culture prior to being plated onto a substratum exhibited similar growth on laminin or collagen. The increase in regeneration by E15 neurons on laminin was augmented, by 22%, if nerve growth factor was supplemented to the culture medium. These results demonstrate that laminin is a better substratum, as compared to collagen, for the elongation of neurites from axotomized SBF neurons. Nonaxotomized neurites, on the other hand, do not appear to prefer one substratum over the other. Furthermore, regeneration from embryonic, SBF neurons on laminin is augmented if NGF is used simultaneously.
以往的研究表明，胚胎期（未切断轴突的）和再生期的中枢神经系统神经元对相同的底物有不同的反应。在本研究中，我们使用了一种体外模型来测试层粘连蛋白和I型胶原促进未切断轴突和切断轴突的胚胎隔区-基底前脑（SBF）神经元神经突生长的能力。来自胚胎第15天（E15）大鼠的外植体中的神经元伸出的神经突在胶原或层粘连蛋白底物上表现出相似的生长特征。如果E15神经元在体外被切断轴突，随后重新接种到层粘连蛋白底物上，它们可以被诱导在层粘连蛋白上伸出更长的神经突。羰花青染料DiI表明，被切断轴突的神经元能够存活并再生突起。这些再生的神经突在层粘连蛋白上比在胶原上生长长27%。同样，原位切断轴突的神经元，即E18 SBF神经元，在层粘连蛋白底物上伸出的神经突长29%。相比之下，在接种到底物之前保持悬浮培养的E15外植体在层粘连蛋白或胶原上表现出相似的生长。如果在培养基中添加神经生长因子，E15神经元在层粘连蛋白上的再生增加22%。这些结果表明，与胶原相比，层粘连蛋白是切断轴突的SBF神经元神经突伸长的更好底物。另一方面，未切断轴突的神经突似乎并不偏好一种底物胜过另一种。此外，如果同时使用NGF，胚胎SBF神经元在层粘连蛋白上的再生会增强。
