Objective:To examine the therapeutic effects and molecular mechanisms of nuclear receptor NR4A1 in alleviating postoperative ileus (POI) in a rat model.Methods:Twenty-four Sprague-Dawley rats were randomly(random number) divided into four groups ( n=6/group): sham-operated control, POI model, POI model + NR4A1 stimultior (Cytosporone B, 13 mg/kg), and POI model + NR4A1 antagonist (DIM-C-pPhCO2Me, 2 mg/kg). After 24 hours, intestinal tissues and serum were collected for analysis. We assessed: (1) histopathological changes, (2) intestinal motility via propulsion rate, (3) NR4A1 expression by immunohistochemistry, (4) epithelial apoptosis via TUNEL assay, (5) inflammatory cytokines (IL-6, IL-4) by ELISA, (6) tight junction protein (occludin) by Western blot, and (7) p38MAPK/NF-κB pathway activation through combined western blot and immunofluorescence analyses. Results:Compared with sham controls, POI model rats showed (all P<0.05): significantly reduced NR4A1 expression, severe mucosal damage, increased inflammatory infiltration, elevated epithelial apoptosis, decreased occludin expression, impaired intestinal motility, upregulated pro-inflammatory cytokines (IL-6, IL-4), and activated p38MAPK/NF-κB signaling. NR4A1 activation with Cytosporone B significantly reversed these pathological changes (all P<0.05), while NR4A1 inhibition exacerbated them. Conclusions:NR4A1 activation attenuates POI by suppressing p38MAPK/NF-κB-mediated inflammation and preserving intestinal barrier function, suggesting its potential as a therapeutic target for postoperative ileus.