Department of Anatomy and Neuroscience, Centre for Neuroscience Research, The University of Melbourne, Parkville, Australia.
PLoS One. 2012;7(5):e37635. doi: 10.1371/journal.pone.0037635. Epub 2012 May 22.
Mice lacking the axon guidance molecule EphA4 have been shown to exhibit extensive axonal regeneration and functional recovery following spinal cord injury. To assess mechanisms by which EphA4 may modify the response to neural injury a microarray was performed on spinal cord tissue from mice with spinal cord injury and sham injured controls. RNA was purified from spinal cords of adult EphA4 knockout and wild-type mice four days following lumbar spinal cord hemisection or laminectomy only and was hybridised to Affymetrix All-Exon Array 1.0 GeneChips™. While subsequent analyses indicated that several pathways were altered in EphA4 knockout mice, of particular interest was the attenuated expression of a number of inflammatory genes, including Arginase 1, expression of which was lower in injured EphA4 knockout compared to wild-type mice. Immunohistological analyses of different cellular components of the immune response were then performed in injured EphA4 knockout and wildtype spinal cords. While numbers of infiltrating CD3+ T cells were low in the hemisection model, a robust CD11b+ macrophage/microglial response was observed post-injury. There was no difference in the overall number or spread of macrophages/activated microglia in injured EphA4 knockout compared to wild-type spinal cords at 2, 4 or 14 days post-injury, however a lower proportion of Arginase-1 immunoreactive macrophages/activated microglia was observed in EphA4 knockout spinal cords at 4 days post-injury. Subtle alterations in the neuroinflammatory response in injured EphA4 knockout spinal cords may contribute to the regeneration and recovery observed in these mice following injury.
缺乏轴突导向分子 EphA4 的小鼠在脊髓损伤后表现出广泛的轴突再生和功能恢复。为了评估 EphA4 可能改变神经损伤反应的机制，我们对脊髓损伤和假损伤对照小鼠的脊髓组织进行了微阵列分析。从 EphA4 敲除和野生型小鼠的脊髓中纯化 RNA，这些小鼠在腰椎脊髓半切或椎板切除后 4 天仅进行了脊髓损伤，然后将其杂交到 Affymetrix All-Exon Array 1.0 GeneChips™上。虽然后续分析表明 EphA4 敲除小鼠的几个通路发生了改变，但特别有趣的是一些炎症基因的表达减弱，包括精氨酸酶 1，其在 EphA4 敲除小鼠中的表达低于野生型小鼠。然后对 EphA4 敲除和野生型脊髓中的不同免疫反应细胞成分进行了免疫组织化学分析。虽然半切模型中浸润的 CD3+T 细胞数量较少，但在损伤后观察到了强烈的 CD11b+巨噬细胞/小胶质细胞反应。在损伤后 2、4 或 14 天，EphA4 敲除和野生型脊髓中的巨噬细胞/激活小胶质细胞的总数或分布没有差异，然而在 EphA4 敲除脊髓中，4 天时 Arg 免疫反应性巨噬细胞/激活小胶质细胞的比例较低。损伤后 EphA4 敲除脊髓中神经炎症反应的细微改变可能有助于这些小鼠在损伤后的再生和恢复。
