A single dose of HU abolishes the induction of systemic inflammation and leukocyte recruitment by H2O-mediated hemolysis in C57BL/6 mice. (A) Plasma Hb levels in C57BL/6 mice at 15 minutes after receiving H2O or saline (150 µL IV) in the presence of HU or vehicle (250 mg/kg IV); n = 4 to 11 mice. (B) Inflammatory status was analyzed by IVIS at 15 minutes after administration of H2O or saline (150 µL IV) in the presence of HU (250 mg/kg IV) or vehicle; n = 4 to 9 mice. WBC (C) rolling, (D) adhesion, and (E) extravasation determined 15 minutes after coadministration of saline or H2O (150 µL IV) plus HU or vehicle (250 mg/kg IV); n = 28 to 33 venules in 3 to 4 mice. *P < .05, **P < .01, and ***P < .001 compared with saline; ∞P < .05 compared with saline + HU; ●●●P < .001 compared with H2O; ##P < .01 and ###P < .001 compared with H2O + vehicle.