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Analysis of duodenojejunal flexure formation in mice: implications for understanding the genetic basis for gastrointestinal morphology in mammals
Author(s) -
Onouchi Sawa,
Ichii Osamu,
Otsuka Saori,
Hashimoto Yoshiharu,
Kon Yasuhiro
Publication year - 2013
Publication title -
journal of anatomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 118
eISSN - 1469-7580
pISSN - 0021-8782
DOI - 10.1111/joa.12093
Subject(s) - anatomy , biology , morphology (biology) , retinoic acid , genetics , gene
The mammalian gut undergoes morphological changes during development. We studied the developing mouse duodenojejunal flexure (DJF) to elucidate the mechanism of formation. During embryonic days 10.75–13.75, DJF formation was morphologically classified into three stages: the expansion stage, flexure formation stage, and flexure elongation stage. From the expansion to the flexure formation stages, the DJF wall showed asymmetric morphology and proliferation along the left‐right intestinal axis. From the flexure formation to the flexure elongation stage, the DJF started to bend dorsally with counterclockwise rotation along the antero‐caudal intestinal axis, indicating that the original right side of the duodenum was rotated towards the dorsal body wall during development of the DJF. The direction of attachment of the dorsal mesentery to the DJF did not correspond to the bending direction of the DJF during flexure formation, and this finding indicated that the dorsal mesentery contributed very little to DJF formation. During DJF formation, Aldh1a2 and hedgehog mRNAs were detected at the DJF, and their expression levels differed along the bending axis. In conclusion, DJF formation might be triggered by asymmetric morphology and proliferation along the left‐right intestinal axis under the control of retinoic acid and hedgehog signaling.