Max-Planck-Institute for Psychiatry, Department of Neuromorphology, Martinsried (F.R.G.).
Restor Neurol Neurosci. 1991 Jan 1;2(4):181-98. doi: 10.3233/RNN-1991-245605.
Transection of the rat sciatic nerve induces retrograde changes in the dorsal root ganglia (DRG) neurons and in the motoneurons in the ventral grey matter of the lumbar L4-L6 spinal cord segments. In the ipsilateral dorsal grey matter and in the ipsilateral nucleus gracilis, transganglionic changes occur in the terminal fields of the centrally projecting axons of injured DRG neurons. As revealed by immunocytochemistry, the neuronal reactions were associated with a rapid proliferation and activation of microglial cells in the lumbar spinal cord as well as in the nucleus gracilis. Reactive microglial cells were detected as early as 24 h after sciatic axotomy. The microglial reaction had a maximum around day 7 postlesion and disappeared around 6 weeks after axotomy. In addition to light microscopy, activated, perineuronal microglia were identified by immuno-electron microscopy in the ventral grey matter. In the DRG, satellite cells constitutively expressed major histocompatibility complex (MHC) class II antigens. Sciatic axotomy led to a proliferation of satellite cells and an increased expression of MHC class II molecules in particular. This satellite cell reaction started 24 h after axotomy and continued to increase gradually until about 6 weeks after the lesion. Resident macrophages, detected in the DRG interstitial tissue by their expression of monocyte/macrophage markers, also reacted to sciatic axotomy. Our data suggest that (1) sciatic axotomy leads to a rapid microglial reaction in both the ventral and dorsal grey matter of the lumbar spinal cord and in the ipsilateral nucleus gracilis; (2) the immunophenotype of activated microglia following sciatic axotomy is comparable with that observed after axotomy of cranial nerves, e.g. the facial nerve; (3) satellite cells in DRG constitutively express MHC class II molecules; and (4) sciatic axotomy leads to a rapid activation of satellite cells and interstitial macrophages in the axotomized DRG.
切断大鼠坐骨神经会导致背根神经节 (DRG) 神经元和腰骶段 (L4-L6) 脊髓腹侧灰质中的运动神经元发生逆行性变化。在同侧背侧灰质和同侧薄束核中，损伤的 DRG 神经元的中枢投射轴突的终末场会发生跨神经节变化。免疫细胞化学显示，神经元反应与腰髓和薄束核中神经胶质细胞的快速增殖和激活有关。在坐骨神经切断后 24 小时即可检测到反应性小胶质细胞。小胶质细胞反应在损伤后第 7 天左右达到最大值，并在切断后 6 周左右消失。除了光镜外，免疫电子显微镜还在腹侧灰质中鉴定出激活的、围绕神经元的小胶质细胞。在 DRG 中，卫星细胞持续表达主要组织相容性复合物 (MHC) Ⅱ类抗原。坐骨神经切断导致卫星细胞增殖和 MHC Ⅱ类分子表达增加。这种卫星细胞反应始于切断后 24 小时，并持续逐渐增加，直到损伤后约 6 周。通过其单核细胞/巨噬细胞标志物的表达，在 DRG 间质组织中检测到的常驻巨噬细胞也对坐骨神经切断做出反应。我们的数据表明：(1) 坐骨神经切断会导致腰髓腹侧和背侧灰质以及同侧薄束核中迅速发生小胶质细胞反应；(2) 坐骨神经切断后激活的小胶质细胞的免疫表型与颅神经（例如面神经）切断后观察到的相似；(3) DRG 中的卫星细胞持续表达 MHC Ⅱ类分子；(4) 坐骨神经切断会导致切断的 DRG 中的卫星细胞和间质巨噬细胞迅速激活。
