Macias D, Gañan Y, Hurle J M
Departamento de Ciencias Morfologicas, Facultad de Medicina, Universidad de Extremadura, Badajoz, Spain.
Anat Embryol (Berl). 1992;186(1):27-32. doi: 10.1007/BF00710399.
In the chick embryo the interdigital tissue in the stages previous to cell death exhibits in vitro a high chondrogenic potential, and forms extra digits when subjected in vivo to local ectodermal removal. In the present work we have analyzed the chondrogenic potential both in vivo and in vitro of the interdigital mesenchyme of the duck leg bud. As distinct from the chick, the interdigital mesenchyme of the duck leg bud exhibits a low degree of degeneration, resulting in the formation of webbed digits. Our results show that duck interdigital mesenchyme exhibits also a high chondrogenic potential in vitro until the stages in which cell death starts. Once cell death is finished chondrogenesis becomes negative and the interdigital mesenchyme forms a fibroblastic tissue. In vivo the interdigital mesenchyme of the duck leg bud subjected to ectoderm removal forms ectopic foci of chondrogenesis with a range of incidence similar to that in the chick. Unlike those of the chick the ectopic cartilages of the duck are rounded and smaller, and appear to be located at the distal margin of the interdigital mesenchyme. Formation of extra digits in the duck occurs with a lower incidence than in the chick. It is concluded that ectopic chondrogenesis and formation of extra digits is related to the intensity of interdigital cell death. The non-degenerating interdigital mesenchymal cells destined to form the interdigital webs of the duck appear to contribute very little to the formation of interdigital cartilages.
在鸡胚中，细胞死亡前阶段的指间组织在体外表现出较高的软骨形成潜能，并且在体内进行局部外胚层切除时会形成额外的趾。在本研究中，我们分析了鸭腿芽指间间充质在体内和体外的软骨形成潜能。与鸡不同，鸭腿芽的指间间充质退化程度较低，导致蹼状趾的形成。我们的结果表明，鸭指间间充质在体外直到细胞死亡开始的阶段都表现出较高的软骨形成潜能。一旦细胞死亡结束，软骨形成变为阴性，指间间充质形成成纤维组织。在体内，去除外胚层的鸭腿芽指间间充质形成异位软骨形成灶，其发生率范围与鸡相似。与鸡的不同，鸭的异位软骨呈圆形且较小，似乎位于指间间充质的远端边缘。鸭额外趾的形成发生率低于鸡。结论是异位软骨形成和额外趾的形成与指间细胞死亡的强度有关。注定要形成鸭蹼的未退化指间间充质细胞似乎对指间软骨的形成贡献很小。
