AIM: To investigate the differences in injury patts caused by arterial, venous or arteriovenous mesenteric occlusion.METHODS: Male Wistar rats were separated equally into four groups. Occlusion was performed by clamping the superior mesenteric artery (A), the mesenteric vein (V) or both (AV) for 30 min, followed by 60 min of reperfusion. A control group received sham surgery only. Intestinal sections were examined for histological damage and serum tumor necrosis factor-α (TNF-α), endothelin-1 (ET-1), P-selectin, antithrombin Ⅲ (ATⅢ) and soluble intracellular adhesion molecule-1 (ICAM-1) concentrations were measured.RESULTS: All groups showed significant mucosal injury compared to controls. Furthermore, mucosal injury was significantly more severe in the V and AV groups compared to the A group (3.6 ± 0.55, 3.4 ± 0.55 and 2 ± 0.71, respectively, P = 0.01). ICAM-1 was similarly elevated in all groups, with no significant differences between the groups. P-selectin levels were significantly elevated in the V and AV groups but not the A group (1.4 ± 0.5 ng/mL, 2.52 ± 0.9 ng/mL and 0.02 ± 0.01 ng/mL,respectively, P = 0.01) and ET-1 was significantly elevated in the A and V groups but not the AV group (0.32 ± 0.04 pg/mL, 0.36 ± 0.05 pg/mL and 0.29 ± 0.03 pg/mL, respectively, P = 0.01) compared to sham controls. ATⅢ levels were markedly depleted in the V and AV groups, but not in the A group (29.1 ± 5.2 pg/mL,31.4 ± 21.8 pg/mL and 55.8 ± 35.6 pg/mL ,respectively, P = 0.01), compared to controls. Serum TNF-α was significantly increased in all groups compared to sham controls (1.32 ± 0.87 ng/mL, 1.79 ± 0.20 ng/mL and 4.4 ± 0.69 ng/mL, for groups A, V and AV,respectively, P = 0.01), with higher values in the AV group.CONCLUSION: Different patts of response to ischemia/reperfusion are associated with venous, arterial or arteriovenous occlusion. Venous and arteriovenous occlusion was associated with the most severe alterations.