Department of Neurological Intractable Disease Research, Faculty of Medicine, Kagawa University, Kagawa 761-0793, Japan.
Department of Molecular Neurobiology, Faculty of Medicine, Kagawa University, 761-0793, Japan.
Brain Res. 2021 Oct 1;1768:147595. doi: 10.1016/j.brainres.2021.147595. Epub 2021 Jul 29.
The present study aimed to assess spinal tract formation in neurons originating from cervical (C7), brachial (C14), and thoracic (T4) regions, with the lumbar (LS2) region as a reference, in a chick embryo. For the assessment of the spinal tracts, we introduced a vector expressing human placental alkaline phosphatase into progenitor cells generated after neural tube closure and belonging to the above segments, using in ovo electroporation. The ascending axons took primarily similar paths: dorsal commissural, ventral commissural, and dorsal non-commissural paths, with some variance depending on their originating segments. Some populations of non-commissural neurons later extended their axons following a ventral path. The elongation rates of these axons are primarily constant and tended to increase over time; however, some variations depending on the originating segments were also observed. Some of the dorsally ascending axons entered into the developing cerebellum, and spinocerebellar neurons originating from T4 projected their axons into the cortex of the cerebellum differently from those from LS2. These results unveil an overall picture of early ascending spinal tract formation.
本研究旨在评估源自鸡胚颈椎（C7）、臂丛（C14）和胸（T4）区域以及作为参考的腰椎（LS2）区域神经元的脊髓束形成。为了评估脊髓束，我们使用鸡胚电穿孔将表达人胎盘碱性磷酸酶的载体引入神经管闭合后产生的祖细胞中，这些祖细胞属于上述节段。升序轴突主要采取相似的路径：背侧连合、腹侧连合和背侧非连合路径，但其起源节段存在一些差异。一些非连合神经元的群体后来沿着腹侧路径延伸其轴突。这些轴突的伸长率主要是恒定的，并随着时间的推移而增加；然而，也观察到一些与起源节段有关的变化。一些背侧上升轴突进入发育中的小脑，而源自 T4 的脊髓小脑神经元与源自 LS2 的神经元不同，它们将轴突投射到小脑皮质。这些结果揭示了早期上升脊髓束形成的整体情况。
