Protective effect of 17S-epoxy-docosapentaenoic acid against dextran sulfate sodium induced ulcerative colitis in BALB/c mice

Ulcerative colitis (UC ) is difficult to eradicate as it leads to chronic inflammation in the digestive tract due to immune system malfunction. The present study demonstrated the protective effect of 7S,15R-dihydroxy-16S,17S-epoxy-docosapentaenoic acid (diHEP-DPA), which had been previously synthesized, on a dextran sulfate sodium (DSS)-induced BAL B/c mouse model of UC . UC was induced with 4% DSS drinking water for 7 days. Initially, the anti-inflammatory effect of diHEP-DPA was confirmed by demonstrating that lipopolysaccharide-stimulated THP1 cells treated with diHEP-DPA decreased IL -6, TNF-α and nitrite levels by fluorescence-activated cell sorting (FAC S) and Griess reagent kit. The results indicated that the administration of diHEP-DPA at 20 μg/kg significantly reduced the severity of colitis, as determined by hematoxylin and eosin staining. The levels of TNF-α, IL -6 and IL -1β in the colon tissue and serum were significantly reduced in the diHEP-DPA + DSS-treated group compared with in the control group, as determined by FAC S and ELI SA kit. It was also observed that diHEP-DPA decreased myeloperoxidase (MPO) and nitrite levels in the colon tissues of diHEP-DPA + DSS-treated mice, as indicated using commercial MPO and nitric oxide kits. The diHEP-DPA+DSS-treated mice also exhibited decreased expression levels of phosporylated (p)-inhibitor κB protein, p-p65 and inducible nitric oxide synthase in the colon tissue by inhibiting inflammation, which were measured by reverse transcription-quantitative PCR and weatern blot analysis. Overall, the present study demonstrated the protective effect of diHEP-DPA against a severe colitis condition in vivo.