Bernardini S, Cannata S M, Filoni S
Dipartimento di Biologia, II Università di Roma Tor Vergata, Italy.
J Hirnforsch. 1992;33(3):241-8.
The experiments were carried out on larvae of Xenopus laevis at stage 48 (acc. to Nieuwkoop and Faber, 1956). Two different kinds of experiments were performed. Experiment I: Unilateral ablation of either a brachial or lumbar segment of the spinal cord and simultaneous removal of the related ganglia. Experiment II: Simple unilateral removal of either brachial or lumbar spinal ganglia. The results obtained in Experiment I show that not only an extensive restitution of the ablated spinal cord does take place, but the regeneration of spinal ganglia may also occur following migration of neural elements from the regenerating spinal cord. The medullary neuroblasts leave the spinal cord along two paths: i) through projections of the gray matter, probably due to the lack of an effective glia limitans; ii) through the motor fibers leaving the spinal cord to form the ventral roots. The first path is followed occasionally while the second is the one usually used when the ventral roots are present. Data based on animals injected with 5-bromodeoxyuridine and sacrificed at fixed intervals, suggest that ganglion precursors, as well as the medullary neurons and glia, originate in the ependyma. This conclusion is supported by the results of Experiment II which demonstrate that when the spinal cord is left intact no discrete groups of ganglion cells and/or glial cells are formed.
实验在处于48期的非洲爪蟾（根据Nieuwkoop和Faber，1956年）幼体上进行。进行了两种不同类型的实验。实验I：单侧切除脊髓的臂段或腰段，并同时切除相关神经节。实验II：单纯单侧切除臂部或腰部脊髓神经节。实验I获得的结果表明，不仅被切除的脊髓确实发生了广泛的修复，而且在神经元件从再生脊髓迁移后，脊髓神经节也可能发生再生。延髓神经母细胞沿两条路径离开脊髓：i）通过灰质的投射，可能是由于缺乏有效的胶质界膜；ii）通过离开脊髓形成腹根的运动纤维。偶尔会走第一条路径，而当存在腹根时，第二条路径是通常采用的路径。基于注射了5-溴脱氧尿苷并在固定间隔处死的动物的数据表明，神经节前体细胞以及延髓神经元和胶质细胞起源于室管膜。实验II的结果支持了这一结论，该结果表明当脊髓保持完整时，不会形成离散的神经节细胞群和/或胶质细胞群。
