Wu Cheng-Han, Chen Yu-Jen, Wang Mu-Hui, Chiou Ling-Ling, Tseng Wen-Yih Isaac, Lee Hsuan-Shu
Institute of Biotechnology, National Taiwan University, Taipei, Taiwan.
Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan.
PLoS One. 2017 Mar 2;12(3):e0173425. doi: 10.1371/journal.pone.0173425. eCollection 2017.
Axolotls have amazing ability to regenerate their lost limbs. Our previous works showed that after amputation the remnant muscle ends remained at their original location whilst sending satellite cells into the regenerating parts to develop into early muscle fibers in the late differentiation stage. The parental and the newly formed muscle fibers were not connected until very late stage. The present study used non-invasive diffusion tensor imaging (DTI) to monitor weekly axolotl upper arm muscles after amputation of their upper arms. DTI tractography showed that the regenerating muscle fibers became visible at 9-wpa (weeks post amputation), but a gap was observed between the regenerating and parental muscles. The gap was filled at 10-wpa, indicating reconnection of the fibers of both muscles. This was confirmed by histology. The DTI results indicate that 23% of the muscle fibers were reconnected at 10-wpa. In conclusion, DTI can be used to visualize axolotls' skeletal muscles and the results of muscle reconnection were in accordance with our previous findings. This non-invasive technique will allow researchers to identify the timeframe in which muscle fiber reconnection takes place and thus enable the study of the mechanisms underlying this reconnection.
美西螈具有惊人的再生其失去肢体的能力。我们之前的研究表明，截肢后，残留的肌肉末端仍留在其原始位置，同时将卫星细胞输送到再生部位，在分化后期发育成早期肌纤维。亲代肌纤维和新形成的肌纤维直到很晚阶段才连接起来。本研究使用非侵入性扩散张量成像（DTI）每周监测美西螈上臂截肢后的上臂肌肉。DTI纤维束成像显示，再生肌纤维在截肢后9周（wpa）可见，但在再生肌肉和亲代肌肉之间观察到一个间隙。该间隙在截肢后10周被填满，表明两块肌肉的纤维重新连接。组织学证实了这一点。DTI结果表明，在截肢后10周，23%的肌纤维重新连接。总之，DTI可用于可视化美西螈的骨骼肌，肌肉重新连接的结果与我们之前的发现一致。这种非侵入性技术将使研究人员能够确定肌纤维重新连接发生的时间框架，从而能够研究这种重新连接背后的机制。
