Tissue pO₂ in WT and TSP1-null mice after flap treatment using EPR oxymetry. (A) Schematic showing LiPc crystal placement in relation to a dorsal random myocutaneous flap. LiPc crystals were implanted in the dorsal subdermal area of mice 7 days prior to flap elevation. Initial measurements were performed by 700-MHz EPR spectroscopy with a small surface coil to confirm crystal location and calculate basal pO₂ levels. Body temperature of the animals was maintained at 37.5°C ± 0.5°C. Following flap elevation and suturing, measurements were recorded at the indicated times (B). Data represent the mean ± SE of measurements from 4 animals in each group. $P < .05 between proximal and distal against control in WT versus TSP^−/−. *P < .05 between proximal and distal.