Department of Pathology, University of Valencia, Valencia, Spain.
Department of Anesthesiology, Intensive Care, and Pain Management, Hospital Clínico Universitario de Valencia, Valencia, Spain.
J Anat. 2019 Nov;235(5):997-1006. doi: 10.1111/joa.13061. Epub 2019 Jul 26.
Spinal cord stimulation (SCS) applied between T8 and T11 segments has been shown to be effective for the treatment of chronic pain of the lower back and limbs. However, the mechanism of the analgesic effect at these medullary levels remains unclear. Numerous studies relate glial cells with development and maintenance of chronic neuropathic pain. Glial cells are electrically excitable, which makes them a potential therapeutic target using SCS. The aim of this study is to report glia to neuron ratio in thoracic segments relevant to SCS, as well as to characterize the glia cell population at these levels. Dissections from gray and white matter of posterior spinal cord segments (T8, T9, intersection T9/T10, T10 and T11) were obtained from 11 human cadavers for histological analyses. Neuronal bodies and glial cells (microglia, astrocytes and oligodendrocytes) were immunostained, microphotographed and counted using image analysis software. Statistical analyses were carried out to establish significant differences of neuronal and glial populations among the selected segments, between the glial cells in a segment, and glial cells in white and gray matter. Results show that glia to neuron ratio in the posterior gray matter of the human spinal cord within the T8-T11 vertebral region is in the range 11 : 1 to 13 : 1, although not significantly different among vertebral segments. Glia cells are more abundant in gray matter than in white matter, whereas astrocytes and oligodendrocytes are more abundant than microglia (40 : 40 : 20). Interestingly, the population of oligodendrocytes in the T9/T10 intersection is significantly larger than in any other segment. In conclusion, glial cells are the predominant bodies in the posterior gray and white matter of the T8-T11 segments of the human spinal cord. Given the crucial role of glial cells in the development and maintenance of neuropathic pain, and their electrophysiological characteristics, anatomical determination of the ratio of different cell populations in spinal segments commonly exposed to SCS is fundamental to understand fully the biological effects observed with this therapy.
胸段 T8-T11 的脊髓刺激（SCS）已被证明对治疗下背部和四肢的慢性疼痛有效。然而，这些髓内水平的镇痛作用机制尚不清楚。许多研究将神经胶质细胞与慢性神经性疼痛的发展和维持联系起来。神经胶质细胞具有电兴奋性，这使其成为使用 SCS 的潜在治疗靶点。本研究旨在报告与 SCS 相关的胸段的神经胶质细胞与神经元的比率，并描述这些水平的神经胶质细胞群体。从 11 具人体尸体的后脊髓段（T8、T9、T9/T10 交界处、T10 和 T11）的灰质和白质中获得解剖部位，用于组织学分析。用免疫组织化学染色对神经元体和神经胶质细胞（小胶质细胞、星形胶质细胞和少突胶质细胞）进行染色，并用图像分析软件对其进行显微摄影和计数。进行统计分析以确定所选节段之间、节段内的神经胶质细胞之间以及灰质和白质内的神经胶质细胞之间神经元和神经胶质细胞群体的显著差异。结果表明，在 T8-T11 椎体区域的人脊髓后灰质中的神经胶质细胞与神经元的比率在 11:1 至 13:1 之间，尽管各椎体节段之间没有显著差异。神经胶质细胞在灰质中的含量多于白质，而星形胶质细胞和少突胶质细胞的含量多于小胶质细胞（40:40:20）。有趣的是，T9/T10 交界处的少突胶质细胞数量明显多于其他任何节段。总之，神经胶质细胞是人类脊髓 T8-T11 段后灰质和白质的主要细胞。鉴于神经胶质细胞在神经性疼痛的发展和维持中的关键作用及其电生理特性，在脊髓段中确定不同细胞群体的比例对于充分理解这种治疗方法的生物学效应是至关重要的。
