Fujikura K, Inoue S
Jikken Dobutsu. 1985 Oct;34(4):445-58.
The regenerative capacity of hindlimb of Xenopus laevis was investigated by amputating the limbs at four levels in various developmental stages including younger postmetamorphosed froglets. Amputations of limbs were performed at the base of limb in stages 50, 51, 52, 53, 54, 55, 58, and 60 (Nieuwkoop and Faber's table), at the middle of limb bud in stages 50, 51, 52 and 54, and at mid-thigh and mid-shank in stages 58 and 60, and the froglets in 2 and 3 cm in snout-vent length. In the present experiments the regenerative capacity of limbs was expressed by the rate of regeneration and morphogenesis. Tadpoles in the stages after 55 failed to regenerate when the limbs were amputated at base level, but individuals in all the other experimental series exhibited regeneration in various rates irrespective of the level of amputation and the stage. The regenerative capacity increased distally along the proximo-distal axis of the limb when amputated at the same stage, while regeneration was better in younger stages than that in older stages when amputations were made at the same levels. The regenerates obtained by amputation of limbs in stages between 50 and 54, were mainly digitated in that they had 5 toes with 3 claws which is the same pattern with the normal limb, 4 toes with 2 claws, 3 toes with 2 claws or one, and 2 toes with one claw etc. Tadpoles at stage 50 could regenerate toes and claws without defect, but in the later the regenerative capacity gradually declined by reducing the number of toes and claws and accompanied by malformation of skeleton as the stage proceeded. The tadpoles in stages after 58, and the froglets of 2 and 3 cm, produced various types of heteromorphic regenerates of shapes such as cone, spike or rod of which the centra were occupied with cartilage rods. However these regenerates showed no morphological differences according to the developmental stages. These heteromorphic regenerates continued their growth even after one year without any sign of development of digitated feet.
通过在包括幼体变态后小青蛙在内的不同发育阶段的四个水平上截肢非洲爪蟾的后肢，研究了其再生能力。在第50、51、52、53、54、55、58和60阶段（Nieuwkoop和Faber的表格）在肢体基部进行截肢，在第50、51、52和54阶段在肢体芽中部进行截肢，在第58和60阶段在大腿中部和小腿中部进行截肢，以及对吻肛长度为2厘米和3厘米的小青蛙进行截肢。在本实验中，肢体的再生能力通过再生率和形态发生来表示。55阶段之后的蝌蚪在基部水平截肢时无法再生，但所有其他实验组的个体无论截肢水平和阶段如何都表现出不同程度的再生。在同一阶段截肢时，再生能力沿肢体的近远轴向远端增加，而在相同水平截肢时，幼体阶段的再生比成体阶段更好。在第50至54阶段截肢获得的再生肢体主要呈指状，它们有5个脚趾，3个爪子，这与正常肢体的模式相同，4个脚趾，2个爪子，3个脚趾，2个爪子或1个爪子，以及2个脚趾，1个爪子等。50阶段的蝌蚪可以无缺陷地再生脚趾和爪子，但随着阶段的推进，再生能力逐渐下降，脚趾和爪子数量减少，并伴有骨骼畸形。58阶段之后的蝌蚪以及2厘米和3厘米的小青蛙产生了各种类型的异形再生肢体，形状如圆锥、尖刺或棒状，其中心被软骨棒占据。然而，这些再生肢体根据发育阶段没有表现出形态差异。这些异形再生肢体即使在一年后仍继续生长，没有任何指状足发育的迹象。
