Abstract: [Abstract] Objective To analysis the differentially expressed proteins and their biological functions in diseased rectal tissues of patients with obstructed defecation syndrome(ODS). Methods 20 patients with ODS and 10 patients with prolapse of mixed hemorrhoids(without constipation symptoms) were included.All patients underwent stapled transanal rectal resection(STARR) and then rectal specimens were collected.Isobaric tags for relative and absolute quantification(iTRAQ) was used to screen the differentially expressed protein profiles between patients with ODS and with mixed hemorrhoid prolapse,and all differentially expressed proteins were analyzed by Gene Ontology(GO)analysis,Kyoto Encyclopedia of genes and genomes(KEGG) analysis and signal peptide(signalP) analysis. Results A total of 164 proteins(88 up-regulated and 76 down-regulated) were differentially expressed between ODS patients and control part with mixed hemorrhoid prolapse.The biological processes involved mainly include cellular processes,biological regulation and metabolic processes.The cell components involved mainly include biochemical processes and cell structure.The molecular functions involved mainly include binding sites,catalytic activity and Molecular function regulation,etc.The signaling pathways involved mainly include neurodegenerative diseases,endocrine and metabolic diseases and immune diseases. Conclusion There are differences in rectal tissue proteins between ODS patients and non-constipation patients.The biological processes and signal pathways involved in the differentially expressed proteins may be connected with the pathogenesis of ODS.

Key words: obstructed defecation syndrome, differentially expressed protein, isobaric tags for relative and absolute quantification, proteomics, bioinformatics