Abstract
Objective:To systematically examine a role for P-selectin in a model of striated muscle ischemia/reperfusion (I/R). Methods:Ischemia was induced in the cremaster muscle of mice by occluding the main feeding arteriole for 30 minutes. Blood flow was then restored to allow for 60 minutes of reperfusion and leukocyte kinetics were assessed during the control period (before I/R) and at 5, 30, and 60 minutes of reperfusion. To study a role for P-selectin in this model, three different approaches were used: Wildtype animals received fucoidin (10 mg/kg, iv), an anti-P-selectin antibody (RB40.34; 20 mg/animal, iv) at 25 minutes of ischemia, or I/R was induced in P-selectin-deficient mice. Results:Ischemia/reperfusion induced a rapid and significant increase in leukocyte rolling, adhesion, and emigration in wild-type mice. The I/R-induced increase in leukocyte rolling was transient, inasmuch as it was reduced by approximately 50% at 30 minutes of reperfusion, and returned to control levels by 60 minutes. Both fucoidin and an anti-P-selectin antibody completely prevented the I/R-induced increase in leukocyte rolling. The P-selectin-deficient animals exhibited absolutely no baseline leukocyte rolling, adhesion, or emigration. Furthermore, I/R did not induce any increase in leukocyte recruitment in the Pselectin-deficient animals over the first 60 minutes of reperfusion. Conclusion:The results from this study clearly illustrate that P-selectin is absolutely critical in both baseline and I/R-induced leukocyte infiltration in the murine-striated muscle.