[Changes in surface microcirculation of extensor digitorum longus tendon after ischemia-reperfusion of rabbit...

The circulation was stopped by tourniquet in one rabbit hindlimb. After 2 or 5 hr of ischemia, the hindlimb was reperfused. During the first 1 hr of reperfusion, dynamic changes in surface microcirculation of extensor digitorum longus tendon were observed by using intravital microscopy. Particular attention was paid to leukocyte-endothelium adhesion and microvascular perfusion condition. It was found that 1) the number of leukocytes adherent to the venular endothelium of ischemic tissue significantly increased following reperfusion and the degree of increases appeared to be directly related to the duration of ischemic period; 2) reperfusion after 5 hr of ischemia could result in the formation of "no reflow phenomenon" in the ischemic tissues, including "primary no reflow" and "secondary capillary perfusion failure". These results suggest that 1) leukocyte-endothelium adhesion may contribute to the development of ischemia reperfusion injury; 2) in the limbs undergone 5 hr of ischemia, not all injuries that occur after ischemi-reperfusion can be attributed to ischemia reperfusion injury. The injury seen some in areas may be produced by ischemia alone, and in others ischemia-reperfusion-secondary ischemia injury may be responsible.