Expression Of C-kit In Human Fetal, Canine And Rat Esophagus

Objective: To investigate the distribution of c-kit expression in human fetal, canine and rat esophagus.Methods: Esophageal tissue samples were collected from 12 human fetuses, 10 dogs and 10 rats in this study. The specimens were examined with immunofluorescence and immunohistochemistry techniques using anti-c-kit, anti-α-SMA, anti-Neurofilament, anti-SM-Fast and anti-SM-Slow antibodies.Results: (1) In the upper third of the human fetal esophagus, c-kit was expressed in the most inner muscular layer, and some c-kit positive cells were also observed in the submucosal and myenteric plexus regions. In the middle third, c-kit was expressed in both inner and outer muscular layers but the expression level in the inner layer appeared higher than that in the outer layer. The c-kit positive cells were abundant in both layers in the lower third. (2) The c-kit-positive cells were mainly distributed in the regions ofα-SMA-positive smooth muscle cells. The positive cells, both c-kit andα-SMA, were detected in the most inner muscular layer at the upper third of the human fetal esophagus and then gradually increased downward and outward. (3) The co-expression of c-kit andα-SMA was found in some cells at submucosal and myenteric plexus regions in the upper third of human fetal esophagus. (4) At the upper third of human fetal esophagus, NF were expressed in the ganglia and nerve fibres within the myenteric and submucosal plexuses, and the c-kit-positive cells were in close apposition to the NF positive cells. (5)α-SMA, SM-Fast and SM-Slow positive cells were co-localized in muscular layer at the upper third of the human fetal esophagus. The SM-Fast and SM-Slow positive cells were mainly distributed in the outer layer at the upper third. SM-Slow was expressed occasionally in the outer layer at the middle third, and gradually disappeared at the lower third. The SM-Fast positive cells were not detected in the middle and lower third esophagus. (6) The c-kit positive cells were not detected in canine and rat esophagus. (7) At the canine and rat esophagus, theα-SMA positive cells were only detected in vessel wall at the upper and middle third muscular layer. In the lower third of the canine esophagus,α-SMA was expressed in the most inner muscular layer. Theα-SMA positive cells were detected occasionally at the end of the rat esophagus.Conclusion: (1) The distribution of c-kit-positive cells has close relationships with smooth muscle cells in human fetal esophagus. (2) The c-kit-positive cells are probably the interstitial cells of Cajal in human fetal esophagus, and their differentiation may be influenced by the innervation. Interstitial cells of Cajal and smooth muscle cells may develop from the same precursor cells in esophagus. (3) The c-kit-positive cells were not detected in canine and rat esophagus.