Taniguchi Yuka, Sugiura Takuji, Tazaki Akira, Watanabe Kenji, Mochii Makoto
Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Akou, Hyogo 678-1297, Japan.
Dev Growth Differ. 2008 Feb;50(2):109-20. doi: 10.1111/j.1440-169X.2007.00981.x.
Tail regeneration in urodeles is dependent on the spinal cord (SC), but it is believed that anuran larvae regenerate normal tails without the SC. To evaluate the precise role of the SC in anuran tail regeneration, we developed a simple operation method to ablate the SC completely and minimize the damage to the tadpole using Xenopus laevis. The SC-ablated tadpole regenerated a twisted and smaller tail. These morphological abnormalities were attributed to defects in the notochord (NC), as the regenerated NC in the SC-ablated tail was short, slim and twisted. The SC ablation never affected the early steps of the regeneration, including closure of the amputated surface with epidermis and accumulation of the NC precursor cells. The proliferation rate of the NC precursor cells, however, was reduced, and NC cell maturation was retarded in the SC-ablated tail. These results show that the SC has an essential role in the normal tail regeneration of Xenopus larvae, especially in the proliferation and differentiation of the NC cells. Gene expression analysis and implantation of a bead soaked with growth factor showed that fibroblast growth factor-2 and -10 were involved in the signaling molecules, which were expressed in the SC and stimulated growth of the NC cells.
有尾目动物的尾巴再生依赖于脊髓（SC），但据信无尾目幼体在没有脊髓的情况下也能再生出正常的尾巴。为了评估脊髓在无尾目动物尾巴再生中的精确作用，我们开发了一种简单的手术方法，使用非洲爪蟾完全切除脊髓，并将对蝌蚪的损伤降至最低。脊髓被切除的蝌蚪再生出了扭曲且较小的尾巴。这些形态异常归因于脊索（NC）的缺陷，因为脊髓被切除的尾巴中再生的脊索短、细且扭曲。脊髓切除从未影响再生的早期步骤，包括用表皮封闭截肢表面以及脊索前体细胞的积累。然而，脊髓被切除的尾巴中脊索前体细胞的增殖率降低，并且脊索细胞成熟延迟。这些结果表明，脊髓在非洲爪蟾幼体的正常尾巴再生中起着至关重要的作用，特别是在脊索细胞的增殖和分化方面。基因表达分析以及植入浸泡有生长因子的珠子表明，成纤维细胞生长因子-2和-10参与了信号分子，这些信号分子在脊髓中表达并刺激脊索细胞的生长。
