Anesthetize rats with urethane (2 g/kg body weight, i.m.). 2. Make a midline incision (20–30 mm) to open the abdomen. 3. Exteriorize and mount the ileocecal portion of the mesentery on a transparent plastic stage. 4. Maintain the mesentery at 37 ºC with continuous saline superfusion. 5. Select venules (30–50 μm diameter, >200 μm length) for study. If the selected venule shows leukocyte adhesion or excessive rolling leukocytes, repeat the selection process. 6. Ensure no leukocyte adhesion and <10 rolling leukocytes within 10 minutes. 7. Induce ischemia by ligating the anterior mesenteric artery and vein for 10 min. 8. Reperfusion: cut the snare to restore blood flow. If reperfusion is not successful, repeat the ligation and reperfusion steps. 9. Observe microcirculation using LOSOM to track leukocyte rolling and adhesion.