Effect of rPSGL-Ig on ischemia/reperfusion–induced leukocyte rolling.

(A) Effect of rPSGL-Ig pretreatment. Mice were subjected to 1 hour lower-body ischemia by application of an infrarenal cross-clamp. Surgery control mice received a laparotomy but no clamp. Some mice received rPSGL-Ig (1 mg/kg, intravenously) 5 minutes prior to release of the aortic clamp. Mice were prepared for intravital microscopy 30 minutes after release of the aortic clamp, and leukocyte rolling in venules was recorded. (B) Effect of rPSGL-Ig treatment after development of I/R-induced rolling. Mice were subjected to 1-hour lower-body ischemia and prepared for intravital microscopy after aortic clamp removal. Low-dose (1 mg/kg) rPSGL-Ig was injected 30 minutes after cremaster surgery, and P-selectin blocking antibody was injected after a further 10 minutes. Data are presented as mean ± SEMs of n = 4 to 6 experiments. Significant difference between rPSGL-Ig– (1 mg/kg) and vehicle-pretreated I/R groups are indicated by *P < .05 or **P < .01.