The relationship of Cajal interstitial cells in different parts of rat gastrointestinal tract and slow transit constipation

Objective To observe distribution characteristics and content change of Cajal interstitial cells in rat gastrointestinal tract of the model of slow transit constipation,and evaluate the roles of the interstitial cells of Cajal(ICC) in slow transit constipation in rats.Methods Twenty-four healthy Wistar rats were randomly divided to control group and constipated group.In the constipated group,the rats were daily administered with diphenoxylate(8 mg/kg) to develop slow transit constipation,while the control rats were fed with normal saline.The number and the weight of fecal granule and the body weight of rats were recorded every 5 days for 90 days.Transit functions of gastrointestinal movement were examined by an activated charcoal suspension pushing test one week after stopping the administration of diphenoxylate.The distribution of ICC positive cells confirmed with symbolic c-kit+ cells in stomach,small intestine and the colonic wall were observed by immunohistochemical methods.Results The daily number of fecal granule in the constipated group was significantly less than that in the control group(P0.01).The mean weight of each fecal granule in the constipated group was significantly higher than that in the control group(P0.05).The discharge time of the first granule of black faeces in the constipated group was significantly longer than that in the control group(P0.05).Compared with the control group,there were no significant differences of ICC positive cells in the gastric antrum in the constipated group(P0.05).The number of c-kit+ cells in small intestine and the distal colonic wall in the constipated group was significantly reduced compared with the control group(P0.05).Conclusion In the model of slow transit constipation,ICC number in the gastric antrum was not change significantly.Decreasing trend of ICC number in the small intestine may have some influence on the incidence of STC.The visible reduction of ICC number in the distal colon may be contributed to the pathogenesis of slow transit constipation in rats.