| [Background and Aims] Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal diseases. The aetiology of IBS is unknown, though the published pathophysiology for it involves disturbed gastrointestinal motility, altered gut sensitivity, brain-gut interaction and abnormality of gut endocrine cells and so on, but none of which can explain all of the symptoms of IBS. In our study, we focused at the alteration of proteins, which exert major biological functions in life. The aim of it is to find the abnormal changes in colon of diarrhea-predominant IBS(D-IBS) patients at protein level, and reveal the possible reason for this disorder.[Materials and Methods] According to the Rome II criteria about functional gastrointestinal disease, we chose four diarrhea-predominant IBS patients, male verse female is just the half in the IBS group. We also selected four healthy volunteers as normal control group. Biopsies were performed from the ileocecal junction and sigmoid colon while doing colonoscopy examination, 3 forceps pieces were taken respectively at each site. The specimen were processed by cold saline water which is contained 0.1% PMSF, and preserved with liquid nitrogen immediately (Finished within 10 minutes after biopsies) . Then after proteins extracted from the specimen and run on the two-dimensional gel electrophoresis, based on the Gorg A's method. Proteins are separated according to charges(pI) by isoelectric focusing(IEF) in the first dimension and the sizes(M_r) by sodium dodecyl sulphate(SDS) polyacrylamide gel electrophoresis(PAGE) in the second dimension. Visualization of two-dimensional electrophoresis gel under the Coomassie brilliant blue, the gel map was gotten with scanner. The scanning maps were analyzed with the software Image Master 2D Elite and the obviousabnormal protein spots were differentiated. Mass spectrometry was performed with the spots which were significantly different and easily to isolate with others, the search for the functions of the identified proteins on the special websites.[Results] Proteomics maps of human being colon mucosa were obtained successfully with 2-dimensional gel electrophoresis (2-DE). Average protein spots are 336 in normal control group, and the matching rate among it is 91.83%, while in D-IBS group, average protein spots are 426, and the matching rate is 94.60%. The average matching rate between the test group and the control group is 74%. The results show that all together 24 spots displayed quantitative changes, (Volume value>2.0 times), among them, 3 protein spots decreased in abundance and 21 showed higher expression. Four protein spots which up-regulated or down-regulated most obviously were chosen to be performed mass spectrometry analysis, and all of them were identified. Immunoglobulin J chain, heat shock protein 27, which are up-regulated. While the other down-regulated two are hemoglobin beta subunit and fructose-bisphosphate aldolase A.[Conclusion] By using the 2-dimensional gel electrophoresis (2-DE) technique, 2-DE maps of colonic mucosa were obtained. We found 24 abnormal expression proteins from the colon in D-IBS and identified four spots which changed the most obviously. The D-IBS aetiology may be associated with the down-regulation or up-regulation of some proteins, the proteins may include Immunoglobulin J chain, heat shock protein 27, hemoglobin beta subunit and fructose-bisphosphate aldolase A. |
PDF Full Text Request