The digestive tract and derived primordia differentiate by following a precise timeline in human embryos between Carnegie stages 11 and 13.
The digestive tract and derived primordia differentiate by following a precise timeline in human embryos between Carnegie stages 11 and 13.
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消化道和衍生原基的分化遵循人类胚胎在卡内基第 11 阶段和第 13 阶段之间的精确时间线。
DOI：
10.1002/ar.23314
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Takakuwa T.
中科院分区：
文献类型：
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作者：
Ueno S;Yamada S;Uwabe C;Maenner J;Shiraki N;Takakuwa T.
在体节阶段，消化道发育的确切机制仍然不清楚。在这项研究中，我们研究了人类体节期胚胎消化道源性原基分化的形态学和精确的时间轴。我们选择了37个卡内基阶段（CS）11-CS 13（受精后28-33天）的人类胚胎，并使用组织学连续切片重建的图像对所有样本中消化道和衍生原基的形态和定位进行了三维分析。消化道最初由卵黄囊变窄形成，然后在CS 12（21-29体节）和CS 13（≥ 30体节）期间分化出几个衍生原基，如咽、肺、胃、肝和背胰原基。所有CS 13胚胎的四对咽囊分化完成。呼吸原基在≥ 26体节的胚胎中被识别，并在CS 13变平，然后分支。在≥ 35体节的胚胎中，气管形成，然后伸长。所有≥ 34体节胚胎的胃呈纺锤形，≥ 27体节胚胎的肝芽被识别。除了3个CS 13胚胎外，所有CS 13胚胎的背胰都表现为明确的芽殖，在这些芽殖周围，小肠在≥ 33体节胚胎中弯曲。在≥ 35体节的胚胎中，小肠围绕头尾轴旋转，并开始形成原始的肠环，导致脐疝。这些数据表明，消化道和衍生的原基分化遵循一个精确的时间轴，并表现出有限的个体差异。Anat Rec，299：439-449，2016.© 2016 Wiley Periodicals，Inc.
The precise mechanisms through which the digestive tract develops during the somite stage remain undefined. In this study, we examined the morphology and precise timeline of differentiation of digestive tract‐derived primordia in human somite‐stage embryos. We selected 37 human embryos at Carnegie Stage (CS) 11–CS13 (28–33 days after fertilization) and three‐dimensionally analyzed the morphology and positioning of the digestive tract and derived primordia in all samples, using images reconstructed from histological serial sections. The digestive tract was initially formed by a narrowing of the yolk sac, and then several derived primordia such as the pharynx, lung, stomach, liver, and dorsal pancreas primordia differentiated during CS12 (21–29 somites) and CS13 (≥ 30 somites). The differentiation of four pairs of pharyngeal pouches was complete in all CS13 embryos. The respiratory primordium was recognized in ≥ 26‐somite embryos and it flattened and then branched at CS13. The trachea formed and then elongated in ≥ 35‐somite embryos. The stomach adopted a spindle shape in all ≥ 34‐somite embryos, and the liver bud was recognized in ≥ 27‐somite embryos. The dorsal pancreas appeared as definitive buddings in all but three CS13 embryos, and around these buddings, the small intestine bent in ≥ 33‐somite embryos. In ≥ 35‐somite embryos, the small intestine rotated around the cranial‐caudal axis and had begun to form a primitive intestinal loop, which led to umbilical herniation. These data indicate that the digestive tract and derived primordia differentiate by following a precise timeline and exhibit limited individual variations. Anat Rec, 299:439–449, 2016. © 2016 Wiley Periodicals, Inc.