Varga Z M, Fernandez J, Blackshaw S, Martin A R, Muller K J, Adams W B, Nicholls J G
Department of Pharmacology, Biocenter, University of Basel, Switzerland.
J Comp Neurol. 1996 Mar 18;366(4):600-12. doi: 10.1002/(SICI)1096-9861(19960318)366:4<600::AID-CNE4>3.0.CO;2-8.
The aim of these experiments was to analyze neurite outgrowth during regeneration of opossum spinal cord isolated from Monodelfis domestica and maintained in culture for 3-5 days. Lesions were made by crushing with forceps. In isolated spinal cords of animals aged 3 days, neurites entered the crush and grew along the basal lamina of the pia mater. Growth cones with pleiomorphic appearance containing vesicles, mitochondria and microtubules were abundant in the marginal zone, as were synaptoid contacts with active zones facing basal lamina. In preparations from animals aged 11-12 days, the lesion site was disrupted and contained only degenerating axons, debris and vesicles. Axons and growth cones entered the edge of the lesion but did not extend into it. Lesions in young animals extended over distances of more than 1 mm and contained no radial glia. The damaged area in older preparations was restricted to the crush site with normal astrocytes, oligodendrocytes and neurons immediately adjacent to the lesion. Thus, similar crushes produced more extensive damage in younger spinal cords that were capable of regeneration than in older cords that were not. Dorsal root ganglion fibers labeled with carbocyanine dye (DiI) were observed by video imaging as they grew through lesions. Individual growth cones examined subsequently by electron microscopy had grown again along pial basal lamina. After 5 days in culture dorsal root stimulation gave rise to discharges in ventral roots beyond the lesion indicating that synaptic connections were formed by growing fibers.
这些实验的目的是分析从家短尾负鼠分离出并在培养中维持3 - 5天的负鼠脊髓再生过程中的神经突生长。通过用镊子挤压造成损伤。在3日龄动物的离体脊髓中，神经突进入挤压部位并沿着软脑膜的基膜生长。在边缘区，具有多形外观、含有囊泡、线粒体和微管的生长锥丰富，与面向基膜的活性区的类突触接触也丰富。在11 - 12日龄动物的标本中，损伤部位被破坏，仅含有变性轴突、碎片和囊泡。轴突和生长锥进入损伤边缘但未延伸至其中。幼龄动物的损伤延伸超过1毫米，且不含放射状胶质细胞。老龄标本中的损伤区域局限于挤压部位，紧邻损伤处有正常的星形胶质细胞、少突胶质细胞和神经元。因此，类似的挤压在能够再生的幼龄脊髓中比在不能再生的老龄脊髓中造成更广泛的损伤。通过视频成像观察用羰花青染料（DiI）标记的背根神经节纤维穿过损伤部位的生长情况。随后通过电子显微镜检查的单个生长锥再次沿着软膜基膜生长。培养5天后，背根刺激在损伤部位以外的腹根中引发放电，表明生长的纤维形成了突触连接。
