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Impairment of esophageal skeletal muscle in type XIX collagen mutant mouse

: Type XIX collagen is an extremely rare extracellular matrix collagen thought to be involved in the formation of basement membrane zones and is transiently expressed by differentiating muscle cells. Mice without collagen XIX exhibit an impaired muscle differentiation and function. Individual skeletal muscle fibers are ensheathed by a meshwork of collagen fibers comprising the endomysium. Such structures seem to play an important role in resisting imputes. Type XIX collagen-null mice have a poor survival, and surviving null mice exhibit a dilated esophagus after three months of age, especially in aged mice. We used scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to examine the skeletal muscle morphology and reticular distribution of collagen fibers in the endomysium of the esophagus in mice. The aim of this research was to demonstrate the fine structures in the dilated portion of the esophagus in mutant mice. Our findings showed that the size and arrangement of skeletal muscle as well as the collagen fibrils of the endomysium in the dilated portion of the esophagus differed markedly from those in wild-type mice. In addition, skeletal abnormalities were seen in the non-dilated portion of the esophagus in the mutant mice. These findings suggest that type XIX collagen-containing fibrils influence morphogenesis during skeletal myogenesis in the murine esophagus.