Temporal and spatial relationship between no-reflow phenomenon and postischemic necrosis in skeletal muscle

The aim of these experiments was to describe clearly the spatial relationship between the no-reflow phenomenon and tissue injury in postischemic skeletal muscle. Using the rectus femoris muscle of anesthetized rabbits, we examined microvascular perfusion in untreated muscles and in muscles after 3.5 h of ischemia and 10 min, 1 h, and 24 h of reperfusion. Microvascular perfusion was assessed by infusion of biological ink and quantitation of 1) the area of capillary filling in histological sections, and 2) the ratio of perfused capillaries to muscle fibers in perfused areas (C/F). After 10 min of reperfusion, perfused cross-sectional area had decreased from 67.0 ± 20.0 to 10.6 ± 5.6 (SD)%, and C/F was also significantly reduced. These changes persisted for at least 24 h. After 10 min of reperfusion, flow was randomly distributed throughout the muscle. However, after 24 h, perfusion was confined to the peripheral tissue in areas that were also viable as demonstrated by nitro blue tetrazolium staining. These results show that in this model, in the early stages of reperfusion, flow is established in some areas, which are destined to become necrotic.