Protective Effects of Pachymic Acid in a DSS-Induced Mouse Model of Ulcerative Colitis.

Objective: This study aimed to investigate the protective effects and underlying mechanisms of pachymic acid (PA), a natural triterpenoid compound, in a dextran sulfate sodium (DSS)-induced murine model of ulcerative colitis (UC).

Methods: Disease severity was assessed using the disease activity index (DAI). Histological changes and mucus layer integrity were evaluated via hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) staining. Inflammatory cytokines and oxidative stress markers were measured using ELISA and biochemical assays. DNA damage was assessed by γH2AX immunofluorescence. Protein expression levels of tight junction markers, apoptosis regulators, and NF-κB signaling components were analyzed by Western blotting.

Results: PA administration significantly alleviated colitis symptoms, as indicated by reduced DAI scores, mitigation of colon shortening, preservation of colon histoarchitecture, and restoration of mucus secretion. PA suppressed the expression of pro-inflammatory cytokines and oxidative stress markers, enhanced endogenous antioxidant activity, and decreased γH2AX levels, indicating reduced DNA damage. Moreover, PA restored tight junction protein expression, improved the Bax/Bcl-2 ratio, and inhibited activation of the NF-κB signaling pathway.

Conclusion: PA effectively ameliorates colonic inflammation and epithelial barrier dysfunction in DSS-induced colitis, suggesting its potential as a therapeutic candidate for ulcerative colitis.