Objective: to investigate morphological changes in the muscular layer and an intermuscular population of interstitial cells of Cajal (ICC) in acute ulcerative colitis induced by dextran sulfate sodium (DSS).

Methods: Acute colitis was induced by 3% DSS (molecular weight 40 kDa) in drinking water for 5 days; a control animal group was given tap water. Longitudinal colonic sections were histologically examined. Immunofluorescence staining of total preparations with antibodies to c-Kit was employed to assess an ICC population.

Results: Morphological examination showed a morphological pattern of acute ulcerative colitis in the DSS-treated mice. The colonic muscular layer was thickened and the cytoplasm of smooth muscle cells was vacuolated. There was a decrease in ICC network density and counts in the muscular layer, as well as a specific c-Kit positive granularity in the ICC bodies and processes.

Conclusions: In acute ulcerative colitis, there are alternative changes in the colonic muscular layer and a decrease in ICC density.