title: Diffusion tensor tractography reveals muscle reconnection during axolotl limb regeneration.
abstract: 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.
authors.affiliation: Institute of Biotechnology, National Taiwan University, Taipei, Taiwan.
authors.forename: Cheng-Han
authors.initials: CH
authors.lastname: Wu
authors.affiliation: Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Yu-Jen
authors.initials: YJ
authors.lastname: Chen
authors.affiliation: Institute of Biotechnology, National Taiwan University, Taipei, Taiwan.
authors.forename: Mu-Hui
authors.initials: MH
authors.lastname: Wang
authors.affiliation: Liver Disease Prevention and Treatment Research Foundation, Taipei, Taiwan.
authors.forename: Ling-Ling
authors.initials: LL
authors.lastname: Chiou
authors.affiliation: Institute of Medical Device and Imaging, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Wen-Yih Isaac
authors.initials: WI
authors.lastname: Tseng
authors.affiliation: Institute of Biotechnology, National Taiwan University, Taipei, Taiwan.|Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.|Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan.
authors.forename: Hsuan-Shu
authors.initials: HS
authors.lastname: Lee
mesh_terms: D000558:Ambystoma mexicanum / Q000502:physiology*; D000818:Animals; D056324:Diffusion Tensor Imaging / Q000379:methods*; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D012038:Regeneration