Preliminary Study On Distribution Of NOS Neurons And Interstitial Cells Of Cajai In The Colonic Myenteric Plexuses Of Rats With Slow Transit Constipation

Objective:The slow transit constipation is thought as a primary defect that the movement of contents from the proximal to the distal colon and rectum is slower than that of normal.Its'clinical features are infrequent faeces,hard faeces,and a feeling of incomplete evacuation.Incidence of slow transit constipation increases along with the improvement of standard of living.However,the aetiology of it remains unclear. The present study was carried out to establish the model of slow transit constipation by feeding rats with Diphenoxylate.To investigate the effects of interstitial cells of cajal of pacemaker cells of g gastrointestinal tract,which product slow wave and conduct electrical excitation and inhibitive neurotransmitter nitrogen monoxide in slow transit constipation motility by the observation on animal models with slow transit constipation.Methods:Twenty health SD rats were used in the study.Male and female(half and half) rats were selected with the body mass of 150-200g.They were assigned randomly into control group and model group with 10 rats in each group.Model group ten rats were used to choose the fittest dosage of Diphenoxylate(8mg/kg) to establish slow transit constipation model.After 120 days,the rats in the control group and the model group were fasting for 24 hours,the time of colonic transit was measured.At last the rats were killed,the colonic tissues were examined by histochemistry for NADPH-diaphorase and immunocytochemistry for C-kit receptor tyrosine kinas.Using quantitative image analysis software for statistical analysis.Resultes:(1) The movement of contents from the proximal to the distal colon and rectum in the model group was significantly slower than that of normal rats.In model rats group,the time of the first black feces was(370±50min),it was significantly longer than that of normal rats(217±35 min,p＜0.01).(2)NOS positive neurons were significantly reduced in the colon of rats with slow transit constipation (positive cells were 5.34±1.10 vs control group8.56±2.89,p＜0.01),ICCs were not well-distributed,the number of ICCs in some area increased but decreased in other area(positive cells were 2.27±1.10 vs control group4.54±1.13,p＜0.01).Conclusion:1.The model of rats with slow transit constipation was successfully established.;2.Abnormal distribution and decreased numbers of NOS positive neurons and interstitial cells of cajal is responsible for colonic motility abnormality.