ABSTRACT
AIM:To study the effects of antagonistic peptides binding specifically with the first and second extracellular loops (ECL1 and ECL2) of C-C chemokine receptor 5 (CCR5) on the colitis rats induced by trinitrobenzenesulfonic acid (TNBS) and the mechanisms.METHODS:The colitis model of SD rats was induced by TNBS (100 mg/kg).The effects of 2 antagonistic peptides at different doses (ECL1:25, 35 and 45 mg/kg;ECL2:15, 25 and 35 mg/kg) on the model rats including the changes of disease activity index (DAI), colon macroscopic damage index (CMDI) and histological grading were observed.The mRNA and protein expression levels of TNF-α and COX-2 in the colonic mucosa were detected by real-time PCR and Western blot, respectively.RESULTS:Compared with model group, the changes of DAI, CMDI and histopathological injury of the rats treated with ECL2 antagonistic peptide HY at an appropriate dose were significantly reduced (P<0.05), and the protein and mRNA expression levels of TNF-α and COX-2 were significantly decreased (P<0.05).However, the effects of ECL1 antagonistic peptide GH on all scores and the expression levels of TNF-α and COX-2 were not obvious.CONCLUSION:ECL2 antagonistic peptide HY relieves TNBS-induced colitis in SD rats via down-regulating the expressions of TNF-α and COX-2 in the colonic mucosa, while the effect of ECL1 antagonist peptide GH was not obvious.
ABSTRACT
Autophagy dysfunction is present in patients with inflammatory bowel disease (IBD), and the single-nucleotide polymorphisms (SNP) of autophagy related genes ATG16L1, NOD2 and IRGM might contribute to an increased susceptibility to IBD.Autophagy might participate in the pathogenesis of IBD through immune response and tolerance, intracellular bacterial infection, abnormalities in immune regulation and Paneth cells, and endoplasmic reticulum stress.This article reviewed the relationship between autophagy abnormalities and pathogenesis of IBD.