Study On Establishment Of An Animal Model Of Slow Transit Constipation And The Formative Mechanism Of Slow Transit Constipation

Objective : To establish an animal model of slow transit constipation and investigate the relationship between interstitial cell of Cajal in colon and the pathological changes in the model of slow transit constipation.Methods : Sixty ICR mice were randomly divided into four groups, fed in SPF environment and administered uniform dosage food and water daily(per day) . According to period of morphine injected, test groups were divided into test group1 (morphine 2.5mg/kg/d*30d,n=15) and test group 2(morphine 2.5mg/kg/d*45d,n=15) , established two corresponding control groups: control group1 (corresponding to test group 1) and control group2(corresponding to test group 2) . The mouse model was established by subcutaneous injection of morphine , and control group was injected same dosage 0.9% sodium chloride solution . Fecal weight was recorded daily, transit function of intestinal movement was measured by activated charcoal suspension pushing test and the changes of interstitial cell of Cajal was observed by immunohistochemical methods.Results :Average daily fecal weight of test group 1 was 18.77 3.23g, Average daily fecal weight of control group 1 was 20.56 1.78g, it showed the significant difference between test group 1 and control group 1 (P<0.05); Average daily fecal weight of test group 2 was 16.84 1.96g, Average daily fecal weight of control group 2 was 22.01 3.24g, it showed the significant difference between test group 2 and control group 2 (P<0.01) . It showed the significant difference of average daily fecal weight between test group 1 and test group 2(P<0.05 ), and there was no difference of average daily fecal weight between control group 1 and control group 2 (P>0.05); intestinal transit ratio of test group 1 was 45.31 1.54%, intestinal transit ratio of control group 1 was 49.17 1.78%, it showed the significant difference between test group 1 and control group 1 (P<0.05); intestinal transit ratio of test group 2 was 40.63 1.31 %, intestinal transit ratio of control group 2 was 50.57 2.99 %, it showed the significant difference between test group 2 and control group2 (P<0.01) . It showed the significant difference of intestinal transit ratio between test group 1 and test group 2 (P<0.05), and there was no difference of intestinal transit ratio between control group 1 and control group 2 (P>0.05); , intestinal c-kit+ cell's area of test group 1 was 81.29 7.91 ten thousand m2, intestinal c-kit+ cell's area of control group 1was 98.58 7.96 ten thousand m , it showed the significant difference between test group 1 and control group 1 (P<0.01);, intestinal c-kit+ cell's area of test group 2 was 66.51 8.42 ten thousand um2, intestinal c-kit+ cell's area of control group 2 was 100.85 9.96 ten thousand m2, it showed the significant difference between test group 2 and control group 2 (P<0.01) . Itshowed the significant difference of intestinal c-kit+ cell's area between test group 1 and test group 2 (P<0.01), and there was no difference of intestinal c-kit+ cell's area between control group 1 and control group 2 (P>0.05)Conclusions : The animal model of slow intestine transit movement induced by morphine conforms with clinical characteristic of slow transit constipation, changes of test groups include average daily fecal weight , intestinal transit ratio and the number of interstitial cells of Cajal had positive correlation with peroid that morphine subcutaneous injection . endogenous opium peptide may lead to reducing of interstitial cell of Cajal, and consequently maybe result in slowing motility of intestine.