Morphometric analysis of secondary palate development in human embryos.
Morphometric analysis of secondary palate development in human embryos.
复制标题
人类胚胎次级腭发育的形态计量分析。
作者：
Nohara A;Owaki N;Matsubayashi J;Katsube M;Imai H;Yoneyama A;Yamada S;Kanahashi T;Takakuwa T.
据报道，由于口鼻腔内结构中与生长相关的平衡变化，发生了二级腭的快速升高和接触以及融合。本研究旨在定量评估复杂的三维形态变化及其对快速运动的影响，例如架高和接触以及融合。使用从 22 个人类胚胎和胎儿样本获得的高分辨率数字化成像数据（相差 X 射线计算机断层扫描和磁共振图像）分析了次级腭形成期间的形态变化。手动重建上颌骨、腭、翼状肌、舌、梅克尔软骨、鼻腔、咽腔和鼻中隔等口鼻结构的三维图像。在卡内基阶段 (CS)21 和 CS22 的所有样本以及 CS23 的三个样本中，腭架均未升高。相比之下，在 CS23 的一个样本中，腭架升高但未接触。此外，在 CS23 的其余四个样本和胎儿早期的所有三个样本中，腭架被抬高并融合。对于每个样本，70 个标志进行了 Procrustes 和主成分 (PC) 分析。 PC-1 占陆架升高前后提取的总变化的 67.4%。值得注意的是，负值组和正值组的 PC-1 值存在显着差异。 PC-2 值在 PC-1 值变化异常缓慢的阶段发生变化，并在 CS22 和 CS23 上半段停止。这一时期被定义为“接近期”，对应于随着腭架抬高、舌头和下颌尖改变其位置和形状以及次级腭架接触和融合而发生动态变化之前的时间。在“接近期”，PC-2变化的测量结果表明，下颌骨（梅克尔软骨和舌头）和上颌骨（腭和鼻腔）上的结构没有改变位置，尽管两组结构似乎前后都被压缩。然而，在架子升高期间和之后，PC-1变化的测量显示上颌和下颌结构之间存在显着变化，特别是舌头上方架子的定位以及舌头和下颌的突出。这些结果表明梅克尔软骨生长在重新定位舌头以促进架子升高方面发挥着积极作用。目前的数据代表了人类次级腭闭合的三个不同阶段，可以促进对腭架水平定位及其融合以成功闭合人类次级腭之前和之后发生的形态生长变化的理解。
Rapid shelf elevation and contact of the secondary palate and fusion reportedly occur due to a growth‐related equilibrium change in the structures within the oro‐nasal cavity. This study aimed to quantitatively evaluate complex three‐dimensional morphological changes and their effects on rapid movements, such as shelf elevation and contact, and fusion. Morphological changes during secondary palate formation were analyzed using high‐resolution digitalized imaging data (phase‐contrast X‐ray computed tomography and magnetic resonance images) obtained from 22 human embryonic and fetal samples. The three‐dimensional images of the oro‐nasal structures, including the maxilla, palate, pterygoid hamulus, tongue, Meckel's cartilage, nasal cavity, pharyngeal cavity, and nasal septum, were reconstructed manually. The palatal shelves were not elevated in all the samples at Carnegie stage (CS)21 and CS22 and in three samples at CS23. In contrast, the palatal shelves were elevated but not in contact in one sample at CS23. Further, the palatal shelves were elevated and fused in the remaining four samples at CS23 and all three samples from the early fetal period. For each sample, 70 landmarks were subjected to Procrustes and principal component (PC) analysis. PC‐1 accounted for 67.4% of the extracted gross changes before and after shelf elevations. Notably, the PC‐1 values of the negative and positive value groups differed significantly. The PC‐2 value changed during the phases in which the change in the PC‐1 value was unnaturally slow and stopped at CS22 and the first half of CS23. This period, defined as the “approach period”, corresponds to the time before dynamic changes occur as the palatal shelves elevate, the tongue and mandibular tip change their position and shape, and secondary palatal shelves contact and fuse. During the “approach period”, measurements of PC‐2 changes showed that structures on the mandible (Meckel's cartilage and tongue) and maxilla (palate and nasal cavity) did not change positions, albeit both groups of structures appeared to be compressed anterior–posteriorly. However, during and after shelf elevation, measurements of PC‐1 changes showed significant changes between maxillary and mandibular structures, particularly positioning of the shelves above the tongue and protrusion of the tongue and mandible. These results suggest an active role for Meckel's cartilage growth in repositioning the tongue to facilitate shelf elevation. The present data representing three distinct phases of secondary palate closure in humans can advance the understanding of morphological growth changes occurring before and after the horizontal positioning of palatal shelves and their fusion to close the secondary palate in humans successfully.