Expression of endothelial surface adhesion molecules in exteriorized cremaster muscle tissues of TNF-α–treated SCD mice. Endothelial cell expression of (A) ICAM-1, (B) P-selectin, and (C) E-selectin in cremaster muscle tissues isolated from SCD mice in steady state or after TNF-α administration in the presence or absence of HU and BAY 73-6691 or drug vehicle, n = 37-69 venules PECAM-1⁺ vascular areas quantified from 4-6 mice per group (*P < .05, ***P < .0001 compared with SCD mice in steady state; ###P < .0001 compared with TNF-α–stimulated SCD mice without HU and BAY-73-6691). (D) Representative images of ICAM-1, P-selectin, and E-selectin expression in cremaster muscle isolated from TNF-α–stimulated SCD mice at the end of the in vivo observation period. Scale bar: 20 μm.