Abstract: Objective · To observe the effect of curcumin on intestinal ischemia/reperfusion (I/R) injury in the rats after cardiopulmonary resuscitation (CPR), and explore the mechanism. Methods · Twenty-four healthy male SD rats were randomly divided into 4 groups, namely control group (Sham group, n=6), curcumin group (Cur group, n=6), intestinal I/R injury after CPR group (I/R group, n=6), and curcumin+intestinal I/R injury after CPR group (Cur+I/R group, n=6). Tracheal and femoral artery and vein catheterization were carried out after anesthesia in the 4 groups. The cardiac arrest/CPR model was established by asphyxiation in I/R group and Cur+I/R group, while not in the other two groups. Curcumin (100 mg/kg) was injected intraperitoneally 1 min before CPR in Cur+I/R group. Meanwhile, equivalent curcumin was injected intraperitoneally in Cur group, and equivalent dimethylsulfoxide was injected in Sham group and I/R group. Venous blood samples were collected 6, 12 and 24 h after recovery of spontaneous circulation (ROSC) to detect the concentrations of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). The rats were sacrificed 24 h after ROSC, and the concentrations of malondialdehyde (MDA) and glutathione (GSH) and the activity of superoxide dismutase (SOD) in the intestinal tissues were measured. The pathological changes of intestinal tissues were observed by hematoxylin-eosin staining. The apoptosis of intestinal mucosal epithelial cells was detected by TUNEL assay. Hypoxia-inducible factor-1α (HIF-1α) and caspase-3 expressions in the intestinal tissues were detected by Western blotting. Ultrastructural changes of the intestinal tissues were observed by using transmission electron microscopy. Results · The concentrations of TNF-α and IL-6 in Cur+I/R group at 3 time points were lower than those in I/R group (all P<0.05), while higher than those in Sham group (all P<0.05). The MDA content in Cur+I/R group was lower than that in I/R group (P<0.01), while higher than that in Sham group (P<0.01). The SOD activity and GSH concentration in Cur+I/R group were higher than those in I/R group (both P<0.05), while lower than those in Sham group (both P<0.01). The expression of HIF-1α protein in Cur+I/R group was significantly higher than that in I/R group (P<0.01), but lower than that in Sham group (P<0.01). The expression of caspase-3 protein in Cur+I/R group was significantly lower than that in I/R group (P<0.01), while higher than that in Sham group (P<0.01). Pathological observation showed that ileal