Changes Of Colonic Substance P, Somatostatin, 5-hydroxytryptamine In Irritable Bowel Syndrome

Objectives: Irritable bowel syndrome(IBS) which affect the quality of life of people is a functional gastrointestinal tract disease. The incidence of IBS has the increasing trend year after year. Its cause and mechanism remain unclear. It's thought that IBS is caused by the maladjustment of nerve-internal secretion-immunity network. Substance P(SP),somatostatin(SOM)and 5-hydroxytryptamine(5-HT)are the important factors in the network and nerve transmitters existing in central nerve system and enteric nervous system (ENS) extensively .SP,SOM and 5-HT play an important role in regulation of gastrointestinal motility, sensation and secretion in pathological and normal stats. SP,SOM and 5-HT have been the new focus studied. So it's the aim of this research to Study the roles of SP,SOM and 5-HT in the occurrence and the development of irritable bowel syndrome(IBS).Methods: Of 59 patients with IBS diagnosed by RomeⅢstandard, 30 were enrolled in diarrhoea type group and 29 were enrolled in constipated group. 10 adults without clinical situation were enrolled in control group. There were not pathological changes of colon mucous membranes by colonoscopy and pathology in all patients. Samples from Sigmoid colons mucous membranes fetched by colonscope were prepared for immunocytochemistry in order to observe the expression levels of SP,SOM,5-HT and the number of EC cells in colon mucous membranes of IBS. This experiment's measure data is expressed by x±S, adopting SPSS 12.0 stat software, choosing two-group one-way ANOVA, test levelα=0.05;As for half quantitative result of SP,SOM,5-HT positive cells immunohistochemistry in colon mucous membranes, two-group multiple-samples rank sum test (Kruskal-Wallis Test) and multiple comparision (Nemenyi Test) was adopted. test levelα=0.05.Results: 1 SP was mainly expressed in epithelias, intestines gland cells, lymphocytes, mast cells, neutrophil and fibre tissues of colon mucous membranes. SP-positive stain rates were 86.67%(26/30) in D-IBS group,44.83%(13/29) in C-IBS group and 90%(9/10)in control group. There were significant differences of expression of SP among diarrhea-predominant IBS(D-IBS) group, constipated-predominant IBS(C-IBS) group and control group(P<0.01). The expression of SP in C-IBS group was lower than those of the control group and D-IBS group(P<0.01). The expression of SP in D-IBS group were higher than C-IBS group markedly(P < 0.01), but no significances were found in the control group(P>0.05).2 There have a large number of SOM positive cells in digestive tract. SOM was mainly expressed inδcell and nerve cell of colon mucous membranes. SOM-positive stain rates were 63.33%(19/30) in D-IBS group, 51.72%(15/29) in C-IBS group and 60%(6/10) in control group There were no significant differences of expression intensity of SOM among diarrhea predominant IBS(D-IBS) group, constipated predominant IBS(C-IBS) group and control group(P>0.05).3 5-HT-positive stain rates were 90%(27/30) in D-IBS group, 89.66%(26/29) in C-IBS group and 60%(6/10) in control group There were significant differences of expression of 5-HT among D-IBS group, C-IBS group and control group(P<0.01). The expression of 5-HT in control group is lower than those of the D-IBS group and C-IBS group(P<0.01). There is no difference of expression of 5-HT between the D-IBS group and C-IBS group (P>0.05). The shape of EC cells is orbicular or elliptical, the volume is little and the colour is mainly pale yellow or buffy in control group and the shape of EC cells is taper or rhombus ,the volume is larger and the colour is coffee or black in IBS groups by light microscopy. The EC cells of sigmoid colon in IBS group is increased remarkably compared with that in control group (P<0.05)。There is no difference of the number of EC cells between the D-IBS group and C-IBS group (P>0.05).Conclusions: 1 Changes of SP in colonic mucous membranes may play an important role in IBS. Expressions of SP is obviously increased in colon mucous membranes of D-IBS group, which means that the high expressions of SP was involved in one of the reasons why the patients suffer from abdominal pain, increasing of defecation and the mucus stool.2 There is no difference of expressions of SOM in colon mucous membranes between the control group and IBS group. Expressions of SOM of IBS group may be one reason result in abnormal intestinal inflammatory reaction.3 The increased number of EC cells and active secretion of 5-HT may be one of reasons resulting in abnormal intestinal peristalsis or increased viscero-sensibility and an important etiological factor of IBS.