Muscularis externa of @entity19 esophagus is composed of two skeletal muscle layers in the adult. But less attention is paid to the histogenesis of the muscularis externa of the esophagus, and controversies still exist about the developmental process and the spatio-temporal expression characteristics of muscle-specific proteins during the development of esophageal muscularis externa. To further probe into the developmental pattern of muscularis externa of the @entity19 esophagus and the expression characteristics of different muscle-specific proteins, immunohistochemical and terminal deoxyribonucleotidyl transferase-mediated @entity9342 ( @entity1977 )- @entity1859 nick-end labeling apoptotic staining methods are used to investigate the expression patterns of different muscle-specific proteins and to elucidate the relationship of these protein expressions with the development of muscularis externa of the @entity19 esophagus. Thus, an understanding of the developing esophageal muscularis externa may be important for developing therapeutic strategies for the treatment of @entity1 @entity66 . Serial sections of @entity19 embryos from @entity2085 ( @entity2085 ) 12 to ED18, and full-length esophagi from postnatal first to 5th day were stained with monoclonal antibodies against a-smooth muscle actin ( @entity3113 ), a-sarcomerical actin (a-SCA), @entity11825 , and @entity20383 (MHC), while apoptosis was determined using the terminal deoxyribonucleotidyl transferase-mediated @entity1977 -digoxigenin nick-end labeling assay. The expression of @entity3113 was started at ED12. During the development of ED14-ED15, @entity3113 positive cells were seen extending from the walls of left three, four, and six arch arteries toward the dorsal wall of esophagus. Stronger expression of a-SCA and @entity11825 could be detected at ED14 and ED15, expression intensity in caudal segment and inner layer was stained stronger than that of cranial segment and outer layer, but after ED16, strong expression of a-SCA and @entity11825 was found in the outer layer of muscularis externa. Expression of MHC was first detected in the outer layer of cranial segment of muscularis externa at ED17. At ED18, MHC had extended to the level of thyroid gland, staining intensity in the outer layer and cranial segment was stronger than that of inner layer and caudal segment. One to five days after birth, the thickness of the esophageal muscle layer was obviously increased. Most of the muscle cells in the cranial segment of esophagus showed strong expression of a-SCA and clear cross striations at higher magnification. With progression toward the caudal segment, expression intensity of a-SCA became weaker, but the expression intensity of @entity11825 was the same at different levels of esophagus. The muscle fibers were arranged densely with high expression of MHC in the cranial segment. During the development of esophageal muscularis externa, few apoptotic cells were observed. @entity3113 , a-SCA, @entity11825 , and MHC show different expression patterns. The differentiation of outer layer of esophageal muscularis externa is quicker than that of inner layer, and the caudal segment is quicker than that of the cranial segment. Besides, apoptosis may not participate in the development of esophageal muscularis externa. The smooth muscle cells from arch arteries may participate in the development of esophageal muscularis externa.

Morphology of the developing muscularis externa in the XXXX esophagus.

@entity1 :: ('9606', 'Species') :: ['human'] @entity3113 :: ('11475(Tax:10090)', 'Gene') :: ['a-SMA'] @entity2085 :: ('MESH:D020964', 'Disease') :: ['ED', 'embryonic day'] @entity66 :: ('MESH:D004194', 'Disease') :: ['esophagus diseases'] @entity19 :: ('10090', 'Species') :: ['mouse'] @entity1859 :: ('MESH:D004076', 'Chemical') :: ['digoxigenin'] @entity1977 :: ('CHEBI:17625', 'Chemical') :: ['dUTP'] @entity20383 :: ('MESH:C564253', 'Disease') :: ['monoclonal anti-skeletal myosin'] @entity11825 :: ('13346(Tax:10090)', 'Gene') :: ['desmin'] @entity9342 :: ('MESH:C027078', 'Chemical') :: ['deoxyuridine triphosphate']
@entity19 :: (10090,Species) :: ['mouse']
