Morphological features of the mouse duodenocolic fold in foetus and adult.
Morphological features of the mouse duodenocolic fold in foetus and adult.
复制标题
胎儿和成人小鼠十二指肠结肠皱襞的形态特征。
DOI：
10.1111/joa.13563
复制
发表时间：
2022
影响因子：
2.4
通讯作者：
Atoji Y.
中科院分区：
文献类型：
--
作者：
Onouchi S;Yasuda H;Saito S;Atoji Y.
对于小鼠十二指肠空肠弯曲(DJF)的形态发生机制，我们认为肠管本身和肠系膜是重要的参与者。本文研究了小鼠十二指肠周围肠系膜的形态特征，特别是胚胎期(E)18.5天和成年期的十二指肠结肠皱折。十二指肠结肠皱折是一层肠系膜，位于整个升十二指肠和降结肠之间。在E18.5，在DJF附近的颅区，十二指肠结肠皱折连接了肠系膜根部的结肠系膜和空肠系膜部分。在中段和尾段，十二指肠结肠皱折与结肠系膜相连。有趣的是，随着十二指肠的升行，十二指肠结肠皱折内有一条平滑肌束。平滑肌束从升十二指肠中部的外肌层延续至尾部。胎儿十二指肠结肠皱折的三维成像显示，平滑肌束分别向肠系膜根部的近端和远端有短和长的尖端。在成人期，与E18.5的十二指肠结肠皱折相比，十二指肠结肠皱折具有更薄的结缔组织和更大的表面积。成人十二指肠结肠皱折也含有与胎儿十二指肠结肠皱折相似的平滑肌束。与肠系膜根部的空肠系膜部分相连的十二指肠结肠的一部分似乎与人类的十二指肠上折叠同源，称为十二指肠空肠折叠；相比之下，大多数十二指肠结肠折叠似乎与人类的十二指肠下折叠同源，称为十二指肠结肠折叠。小鼠十二指肠结肠皱折的平滑肌束似乎起到了将十二指肠升段留在腹膜内的作用，因为动物的十二指肠不属于腹膜后器官，这是由于小鼠和人在腹部器官上的重力方向不同。此外，在其位置和人类十二指肠悬吊肌的神经供应方面，平滑肌束有共同点和不共同点，被称为Treitz韧带。这项研究没有足够的证据表明小鼠十二指肠结肠皱折的平滑肌束与人类的十二指肠悬吊肌同源。综上所述，这项研究揭示了小鼠十二指肠结肠皱折的详细结构，包括该皱折与其他肠系膜的关系。尤其是，平滑肌束是小鼠十二指肠皱褶的一种特殊特征，在DJF的形态发生中可能起着多种作用，特别是在十二指肠升段和十二指肠尾曲的发育过程中。
For the mechanism of duodenojejunal flexure (DJF) morphogenesis in mice, we consider the gut tube itself and the gut mesentery as important players. In this study, we focussed on the morphological features of the gut mesentery around the mouse duodenum, especially the duodenocolic fold at embryonic day (E) 18.5 and the adult phase. The duodenocolic fold, a sheet of the mesentery, was located between the entire ascending duodenum and the descending colon. At E18.5, in the cranial area near the DJF, the duodenocolic fold joined both the mesocolon and the mesojejunal part of the root of the mesentery. In the middle and caudal areas, the duodenocolic fold joined the mesocolon. Interestingly, along with the ascending duodenum, the duodenocolic fold contained a smooth muscle bundle. The smooth muscle bundle continued from the outer muscular layer of the middle to the caudal part of the ascending duodenum. The three‐dimensional imaging of the foetal duodenocolic fold revealed that the smooth muscle bundle had short and long apexes towards the proximal and distal parts of the root of the mesentery, respectively. At the adult phase, the duodenocolic fold had a much thinner connective tissue with a larger surface area in comparison with the duodenocolic fold at E18.5. The adult duodenocolic fold also contained the smooth muscle bundle which was similar to the foetal duodenocolic fold. A part of the duodenocolic fold connecting to the mesojejunal part of the root of the mesentery seemed to be homologous to the superior duodenal fold in humans, known as the duodenojejunal fold; by contrast, most of the duodenocolic fold seemed to be homologous to the inferior duodenal fold in humans, known as the duodenomesocolic fold. The smooth muscle bundle in the mouse duodenocolic fold seemed to play a role in keeping the ascending duodenum in the abdominal cavity because the duodenum in animals did not belong to a retroperitoneal organ in contrast to humans owing to the difference in the direction of gravity on the abdominal organs between mice and humans. Moreover, the smooth muscle bundle shared common and uncommon points in its location and nerve supply to the suspensory muscle of the duodenum in humans, known as the ligament of Treitz. This study had insufficient evidence that the smooth muscle bundle of the mouse duodenocolic fold was homologous to the suspensory muscle of the duodenum in humans. In conclusion, this study revealed the detailed structure of the mouse duodenocolic fold, including the relationship between the fold and other mesenteries. Particularly, the smooth muscle bundle is a specific feature of the mouse duodenocolic fold and might play several roles in DJF morphogenesis, especially the ascending duodenum and the caudal duodenal flexure during development.