| Objectives: Irritable bowel syndrome (IBS) is one of commongastrointestinal disorders, characterized by abdominal pain, bloating,constipation or diarrhea. Recently, the incidence of IBS caused by mental,infectious factors was rising due to the change of life and diet. Without anyanatomical abnormality, the pathogeny of IBS is still unclear. The impact onthe work, the quality of life and the medical cost of the patients is significant.5-hydroxytryptamine (5-HT), a monoamine neurotransmitter, widely spreadin the central nervous system and gastrointestinal tract, was involved in theregulation of physiological function, such as gastrointestinal motility, feeding,sleep, mood, cognition, reproduction, and so on. Serotonin transporter(SERT), widely spread in the limbic system of the brain, the gastrointestinaltract chromaffin cell membrane and5-hydroxytryptamine nerve presynapticmembrane, is a carrier protein with a high affinity for5-HT.Most of5-HTwhich played a physiological function in effect location, lose itscorresponding functions quickly because of reuptaking of SERT. SERT genehas polymorphisms area, and results in different genotypes which can affectthe efficiency of SERT gene transcription, mRNA stability, the quantity andaffinity of SERT, and can cause different symptoms such as diarrhea,constipation and so on. Mast cell tryptase (MCT) is an inflammatorymediator which released by activating mast cell through the way ofdegranulation. Through PAR-2pathway, MCT can lead abdominal pain,distension and other symptoms of IBS. Objectives of this study:1. to furtherexplore the pathogeny of IBS;2. to explore difference expressions of SERTand MCT between IBS and the organic gastrointestinal diseases, provide anew theoretical basis for differential diagnosis of IBS and the organicgastrointestinal diseases. Methods: Sample collection:50samples of colonic mucosa werecollected by colonoscopy in our hospital,10samples of diarrhea-predominantIBS(D-IBS) diagnosed by Rome Ⅲ standard;10samples of tubular adenomapolyps;10samples of normal intestinal tissue as a control group,5-10cm faraway from intestinal polyps;10samples of ulcerative colitis（UC）diagnosedby colonoscopy and pathology. There were10samples of colonicadenocarcinoma which were provided by our hospital pathology department.The expressions of SERT and MCT were measured by immunohistochemicalSP method. Three horizons of positive cells of each slice were randomlyselected under the microscope (×400), and their average gray level werecalculated by digital image acquisition system and HPIAS-1000high-resolution colour and pathology report analysis system. Gray level isinversely proportional to the expression level. The higher of the grey level, theexpression level is lower.Statistical analysis: The data of experiment was expressed by means±SD, adopting SPSS13.0software, using single-factor analysis of variance(ANOVA) to analyze the data of all groups. The correlation between twovariables was analyzed by bivariate correlation, the Pearson correlationcoefficient was calculated. Test level p=0.05.Results:1SERT were widely spread in a variety of the colon cells membrane andcytoplasm. The positive cells were brown. SERT gray level of each group wasin normal distribution (in each group p=0.2>0.1). Compared with the controlgroup (154.85±10.50), the SERT gray level of D-IBS group (169.13±10.11)and UC group (173.04±8.40) were increased, which meant the expression ofSERT in these two groups were decreased (p=0.004in D-IBS group&p=0.000in UC group). The SERT gray level in the colon adenocarcinomagroup and the tubular adenoma polyp group were155.22±12.15and148.43±11.74, respectively; compared with the control group, there were no statisticalsignificance (p=0.939in the adenocarcinoma group&p=0.185in thetubular adenoma polyp group). 2MCT was mainly expressed in the cytoplasm of mast cells. Theimmature mast cells was smaller, and their borders were clear; the maturemast cells was bigger, and the phenomenon of degranulation could be seen,and their borders were irregular and ill-defined.MCT gray level of each group was in normal distribution (D-IBS groupp=0.142>0.1, the other four groups of p=0.2>0.1). Compared with thecontrol group MCT grey level (116.41±8.62), D-IBS group (98.69±10.46)and UC group (101.76±7.51) were predominant decreased, the expression ofMCT in these two groups were predominant increased (p=0.000in D-IBSgroup&p=0.002in UC group). The MCT grey level of the tubular adenomapolyp group and the colon adenocarcinoma group were111.40±12.02and109.96±9.29, respectively; compared with the control group, there were nostatistical significance (p=0.247in the tubular adenoma polyp group&p=0.147in the adenocarcinoma group).3The correlation between the expression of SERT and MCT: SERT graylevel was in normal distribution (p=0.2), MCT gray level was in normaldistribution (p=0.2), Pearson correlation coefficient r=-0.47, SERT andMCT were in negative correlation, and there was statistical significance (p=0.001). The higher expression of the MCT, the expression of the SERT waslower.Conclusions:1The expressions of SERT and MCT in D-IBS were significantlydifference with the control group, which might suggest that the decrease ofSERT and the increase of MCT were related to the genesis of D-IBS.2The expressions of SERT and MCT in the colon adenocarcinomagroup and the tubular adenoma polyp group were similar with the controlgroup, SERT and MCT were not related to the genesis of the colonadenocarcinoma and the tubular adenoma polyp.3SERT and MCT can be an index to differentiate D-IBS from the colonadenocarcinoma and the colon tubular adenoma polyp. |
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