Swalla B J, Solursh M
J Embryol Exp Morphol. 1984 Feb;79:243-55.
This paper examines the differentiation of somites from stage-16 or -17 chick embryos cultured with or without notochord in explant cultures. Histological sections of the cultures were stained with a trichrome stain to identify the different kinds of connective tissues formed. Both anterior and posterior (epithelial) somites made muscle, cartilage and loose connective tissue in explant culture. The extent of cartilage differentiation was enhanced by the presence of the notochord, confirming earlier studies. The presence of 1 mM-dibutyryl cAMP in the culture medium increased the amount of muscle found in the explants but by histological criteria did not inhibit chondrogenesis, contrary to earlier reports. The addition of quail ectoderm to the explants stimulated loose connective tissue to form directly beneath it, suggesting for the first time a role of the ectoderm in dermatome differentiation. These results suggest that the epithelial somite has the capacity to differentiate into all three connective tissue types even before it has separated into sclerotome and dermamyotome. The relative amount of different connective tissue types can be influenced by environmental factors, such as adjacent epithelia like the notochord or ectoderm.
本文研究了在组织块培养中，取自16期或17期鸡胚的体节在有无脊索情况下的分化情况。培养物的组织学切片用三色染色法染色，以识别形成的不同类型的结缔组织。在前部和后部（上皮性）体节在组织块培养中均能形成肌肉、软骨和疏松结缔组织。脊索的存在增强了软骨分化的程度，这证实了早期的研究。培养基中存在1 mM - 二丁酰环磷腺苷（1 mM-dibutyryl cAMP）增加了组织块中肌肉的数量，但根据组织学标准，它并未抑制软骨形成，这与早期报道相反。将鹌鹑外胚层添加到组织块中，刺激了疏松结缔组织在其下方直接形成，这首次表明了外胚层在生皮节分化中的作用。这些结果表明，上皮性体节甚至在分离成生骨节和生皮肌节之前就有能力分化为所有三种结缔组织类型。不同结缔组织类型的相对数量会受到环境因素的影响，如脊索或外胚层等相邻上皮组织。
