| Objective We observe the distribution characteristics and content change of Cajalinterstitial cells in gastrointestinal tract of slow transit constipation model rats, so as tofully evaluate the role of ICC in the pathogenesis of STC.Methods We selected twenty-four healthy Wistar rats which were8weeks old andweight (120±10) g. They were randomly assigned to the control group and the STCmodel group（n=12）. In the model group, the rats were daily administered withdiphenoxylate (8mg/kg) to develop slow transit constipation, while the control ratswere fed with normal saline. The number and the weight of fecal granule and the bodyweight of rats were recorded every5days for90days. Transit functions ofgastrointestinal movement were examined by an activated charcoal suspension pushingtest one week after stopping the administration of diphenoxylate. After rats’ dissection,gastric antrum, small intestine, colon tissue was randomly selected. Usinghematoxylin-eosin staining techniques, we observed histopathological changes in thegastrointestinal tract tissue of rats with slow transit constipation. Meanwhile,Thedistribution of ICC positive cells confirmed with symbolic c-kit+cells in stomach，small intestine and the colonic wall were observed by immunohistochemical methods.SPSS16.0statistical package for statistical analysis, measurement data results wasexpressed as mean±standard deviation (x±s). Counted data was represented by thenumber of cases (percentage). Used t tests to show significant difference between twogroups and Wilcoxon test to express grade information.P<0.05was significant.Results Experimental animals were all in the result analysis(No death records).(1) The daily number of fecal granule in the model group (21.17±7.00grain/d)wassignificantly less than that in the control group (34.43±4.61grain/d)(P <0.01). Themean weight of each fecal granule in the model group (175.10±27.70mg/grain) wassignificantly higher than that in the control group (143.03±24.89mg/grain)(P<0.05).(2) The discharge time of the first granule of black faeces in the model group(475.43±62.37min) was significantly longer than that in the controlgroup(350.5±103.84min)(P<0.05).(3) On the fifth day of the modeling, the averageweight between the two groups had no significant differences (P>0.05). But on theninetieth day of the modeling, the average weight of the model group was346.08±25.25g, significantly lower than the control group which was415.57±18.31g, therewas a significant difference (P<0.01).(4) Through visual observation, HE stainingrevealed that histopathological changes in rat gastric mucosa of two groups weresimilar. From the light microscope, we observed inflammatory cells infiltrating part ofsmall intestine mucosa and colon mucosa in model group without obvious ulcers.(5)Compared with the control group，there were no significant differences of ICC positivecells in antral muscular layer in the model group（P>0.05）. The number of c-kit+cellsin small intestine and the distal colonic muscular layer in the model group wassignificantly reduced compared with that in the control group (P<0.05).Conclusion (1) By the average daily fecal grains, the average quality of each feces aswell as the first black discharge time we can determine the success of the STC ratmodel.(2) HE staining revealed that histopathological changes in rat gastric mucosa oftwo groups were similar. The existence of inflammatory cells in small intestine mucosaand colon mucosa may be associated with rat intestinal inflammatory response causedby chronic constipation. It can be inferred that there was no inflammatory response inrat gastric mucosa.(3) Immunohistochemistry showed that the antral muscular layerICC of STC model did not change significantly, suggesting that the incidence of gastric motility and STC may have no direct correlation.(4) A decreasing trend of ICC numberin the small intestine of the model group may have some influence on the incidence ofSTC.(5) The visible reduction of ICC number in the distal colon may be contributed tothe pathogenesis of STC. |
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