Augustine J M
J Embryol Exp Morphol. 1977 Oct;41:175-88.
To investigate whether mesodermal expansion in the area vasculosa is caused by tension produced by outward migration of cells either in the somatic mesoderm or at the mesodermal edge on an ectodermal substratum, stage 18--20 embryos were transferred to a culture dish. There mesodermal expansion proximal to an arrested edge could be compared with that proximal to a moving edge by measuring the amount of vascular elongation occurring in each. A proximo-distal gradient in vascular elongation rate was detected both in normal embryos in ovo and in explants. This gradient was reversed following arrest of the edge, and the rate of vascular elongation proximal to the arrested edge decreased to 60--70% of that proximal to a moving edge. Nearly all of the mesoderm producing this expansion was located in the proximal two-thirds of the area vasculosa, where vascular elongation rate on the stopped side of the explant was not significantly different from that on the moving side. Similar results were obtained in the absence of the ectoderm, and when liquid culture medium was used instead of semisolid medium. It is concluded that tensile force derived from mesodermal migration plays no role in expansion of the proximal two-thirds of the area vasculosa mesoderm.
为了研究血管区中胚层的扩张是否由体细胞中胚层或外胚层基质上中胚层边缘的细胞向外迁移产生的张力所引起，将18 - 20期胚胎转移到培养皿中。在那里，通过测量每个区域发生的血管伸长量，可以将停滞边缘近端的中胚层扩张与移动边缘近端的中胚层扩张进行比较。在正常的鸡胚和外植体中均检测到血管伸长率的近 - 远梯度。边缘停滞后，这种梯度发生逆转，停滞边缘近端的血管伸长率降至移动边缘近端的60 - 70%。几乎所有产生这种扩张的中胚层都位于血管区近端的三分之二处，在外植体停滞侧的血管伸长率与移动侧的血管伸长率没有显著差异。在没有外胚层的情况下，以及使用液体培养基代替半固体培养基时，也获得了类似的结果。得出的结论是，中胚层迁移产生的拉力在血管区中胚层近端三分之二的扩张中不起作用。
