Screening And Identification Of Differential Expression Proteins From The Colon In Constipation-predominant Irritable Bowel Syndrome

[Background and Aims] Irritable bowel syndrome (IBS) is a clinical common disease. It was characterized as functional intestinal diseases, and we think the abnormality of function must have a basement of material, but we do not know what cells or molecules have played roles on the pathophysiology of IBS. In our study, we used the Proteomics technology to study the difference of the protein expression between the colonic mucosa of the constipation-predominant IBS(C-IBS) patients and the healthy, and to found differential proteins which can provide a new research direction for the pathogenesis of IBS.[Materials and Methods] According to the Rome II criteria about IBS, we chose 8 constipation-predominant IBS(C-IBS) patients, male verse female was just the half, and selected 5 healthy volunteers as control group. Biopsies were performed from the ileocecal junction and sigmoid colon while performing colonoscopy examination, 3 pieces were taken respectively at every site. The specimens were cleaned by cold saline water containing 0.1% PMSF and preserved inside the liquid nitrogen immediately. After the protein extraction, we continued two-dimensional gel electrophoresis according to Gorg A's method. The first dimension was isoelectric focusing (IEF), and the second dimension was sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis (PAGE) which can separate proteins according to size (M_r). Then these gels were dyed using the method of silver staining and scanned. We used the software Image Master 2D Elite to analysis these maps and screened the obviously differential proteins on C-IBS group. These proteins were identified by mass spectrometry.[Results] Proteomics maps of each group's colonic mucosa and average maps were all obtained successfully with 2-dimensional gel electrophoresis(2-DE). We analyzed the average maps and obtained 834 spots on control group and 581 spots on C-IBS group, the matching rate was 76.77%. We also found 26 spots displaying quantitative changes(Volume value ≥ 3. 0 times)among the two groups, and 10 proteins were chose to be performed mass spectrometry, and 4 proteins with up-regulated on C-IBS group were identified: ribosomal protein SA, glyceraldehyde3-phosphate dehydrogenas(GAPDH), guanine nucleotide binding protein (G protein), chloride intracellular channel 1, and 1 protein with down-regulated was FBXO16.[Conclusion] By using the 2-dimensional gel electrophoresis (2-DE) technique, satisfactory 2-DE maps of colonic mucosa were obtained. There existed obvious differential expression proteins on C-IBS group; These differential expression proteins on C-IBS group identified by mass spectrometry included ribosomal protein SA, GAPDH, guanine nucleotide binding protein, chloride intracellular channel 1 and FOXO16. These obviously down-regulation or up-regulation proteins maybe have some relationships with IBS, and their function on IBS pathogenesis should be further studied.