An absolute requirement for P-selectin in ischemia/reperfusion-induced leukocyte recruitment in cremaster muscle

Objective: To systematically examine a role for P-selectin in a model of st riated 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 du ring the control period (before I/R) and at 5, 30, and 60 minutes of reperf usion. To study: a role for P-selectin in this model. three different appro aches were used: Wild-type animals received fucoidin (10 mg/kg, iv), an ant i-P-selectin antibody (RB40.34; 20 mg/animal, iv) at 25 minutes of ischemia , or I/R mas induced in P-selectin-deficient mice. Results: Ischemia/reperfusion induced a rapid and significant increase in l eukocyte rolling, adhesion, and emigration in wild-type mice. The I/R-induc ed 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 complet ely prevented the I/R-induced increase in leukocyte rolling. The P-selectin -deficient animals exhibited absolutely no baseline leukocyte rolling, adhe sion, or emigration. Furthermore, I/R did not induce any increase in leukoc yte recruitment in the P-selectin-deficient animals over the first 60 minut es of reperfusion. Conclusion: The results from this study clearly illustrate that P-selectin is absolutely critical in both baseline and I/R-induced leukocyte infiltrat ion in the murine-striated muscle.