Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, United States of America.
PLoS One. 2012;7(2):e30904. doi: 10.1371/journal.pone.0030904. Epub 2012 Feb 13.
Adult MRL/MpJ mice have been shown to possess unique regeneration capabilities. They are able to heal an ear-punched hole or an injured heart with normal tissue architecture and without scar formation. Here we present functional and histological evidence for enhanced recovery following spinal cord injury (SCI) in MRL/MpJ mice. A control group (C57BL/6 mice) and MRL/MpJ mice underwent a dorsal hemisection at T9 (thoracic vertebra 9). Our data show that MRL/MpJ mice recovered motor function significantly faster and more completely. We observed enhanced regeneration of the corticospinal tract (CST). Furthermore, we observed a reduced astrocytic response and fewer micro-cavities at the injury site, which appear to create a more growth-permissive environment for the injured axons. Our data suggest that the reduced astrocytic response is in part due to a lower lesion-induced increase of cell proliferation post-SCI, and a reduced astrocytic differentiation of the proliferating cells. Interestingly, we also found an increased number of proliferating microglia, which could be involved in the MRL/MpJ spinal cord repair mechanisms. Finally, to evaluate the molecular basis of faster spinal cord repair, we examined the difference in gene expression changes in MRL/MpJ and C57BL/6 mice after SCI. Our microarray data support our histological findings and reveal a transcriptional profile associated with a more efficient spinal cord repair in MRL/MpJ mice.
成年 MRL/MpJ 小鼠已被证明具有独特的再生能力。它们能够在不形成疤痕的情况下,用正常组织结构修复耳穿孔或受伤的心脏。在这里,我们提供了 MRL/MpJ 小鼠脊髓损伤 (SCI) 后恢复的功能和组织学证据。对照组 (C57BL/6 小鼠) 和 MRL/MpJ 小鼠在 T9 (胸椎 9) 处进行背侧半切。我们的数据表明,MRL/MpJ 小鼠的运动功能恢复更快、更完全。我们观察到皮质脊髓束 (CST) 的再生增强。此外,我们观察到损伤部位的星形胶质细胞反应减弱,微腔减少,这似乎为受伤轴突创造了更有利于生长的环境。我们的数据表明,星形胶质细胞反应的降低部分是由于 SCI 后损伤诱导的细胞增殖增加减少,以及增殖细胞的星形胶质细胞分化减少。有趣的是,我们还发现增殖性小胶质细胞的数量增加,这可能与 MRL/MpJ 脊髓修复机制有关。最后,为了评估更快的脊髓修复的分子基础,我们检查了 SCI 后 MRL/MpJ 和 C57BL/6 小鼠之间基因表达变化的差异。我们的微阵列数据支持我们的组织学发现,并揭示了与 MRL/MpJ 小鼠更有效的脊髓修复相关的转录谱。