Huang R, Zhi Q, Schmidt C, Wilting J, Brand-Saberi B, Christ B
Anatomisches Institut der Albert-Ludwigs-Universität, Albertstrasse 17, Germany.
Development. 2000 Feb;127(3):527-32. doi: 10.1242/dev.127.3.527.
The somites of vertebrate embryos give rise to sclerotomes and dermomyotomes. The sclerotomes form the axial skeleton, whereas the dermomyotomes give rise to all trunk muscles and the dermis of the back. The ribs were thought to be ventral processes of the axial skeleton and therefore to be derived from the sclerotomes; however, recently a dermomyotomal origin of the distal rib (the costal shaft) was suggested, with only the proximal parts (head and neck of the rib) being of sclerotomal origin. We have re-investigated the development of the ribs in quail-chick chimeras and carried out three experimental series. (1) Single dermomyotomes and (2) single sclerotomes were grafted homotopically, and (3) the ectoderm overlying the unsegmented paraxial mesoderm was removed in the prospective thoracic region. We found that the cells of the dermomyotome gave rise to epaxial and hypaxial trunk muscles, dermis of the back and endothelial cells, but not to ribs. Cells of the sclerotome formed the axial skeleton and all parts of the ribs. Ablation of the ectoderm, which affects dermomyotome development, results in severe malformations of the ribs, probably due to disturbed interactions between dermomyotome and sclerotome. Our results strongly confirm the traditional view of the sclerotomal origin of the ribs.
脊椎动物胚胎的体节产生硬骨节和皮肌节。硬骨节形成中轴骨骼，而皮肌节则产生所有躯干肌肉和背部的真皮。肋骨曾被认为是中轴骨骼的腹侧突起，因此源自硬骨节；然而，最近有人提出远端肋骨（肋骨干）起源于皮肌节，只有近端部分（肋骨的头部和颈部）起源于硬骨节。我们重新研究了鹌鹑 - 鸡嵌合体中肋骨的发育，并进行了三个实验系列。（1）将单个皮肌节和（2）单个硬骨节进行同位移植，（3）在前体胸区域去除覆盖未分段轴旁中胚层的外胚层。我们发现，皮肌节的细胞产生轴上和轴下躯干肌肉、背部真皮和内皮细胞，但不产生肋骨。硬骨节的细胞形成中轴骨骼和肋骨的所有部分。外胚层的切除会影响皮肌节的发育，导致肋骨严重畸形，这可能是由于皮肌节和硬骨节之间的相互作用受到干扰所致。我们的结果有力地证实了肋骨起源于硬骨节的传统观点。
