Blockade of P-selectin does not affect reperfusion injury in hamsters subjected to glutathione inhibition.

P-selectin antibody has been shown to prevent microvascular damage after ischemia reperfusion (I/R). We investigated whether the treatment with anti-P-selectin would attenuate the decrease in capillary perfusion after glutathione (GSH) inhibition in hamster cheek pouch microcirculation subjected to I/R. Animals were treated for 3 days with l-buthionine-[S,R]-sulfoximine (BSO) to inhibit GSH synthesis. P-selectin expression was determined by using an in situ immunofluorescence method in the microvessels. Ischemia was induced by clamping the cheek pouch for 30 min followed by 30 min of reperfusion. Changes in capillary perfusion, RBC velocity, and leukocyte and platelet adhesion on microvessels were measured after I/R. Hamsters subjected to I/R showed increased leukocyte and platelet adhesion as well as decreased capillary perfusion. The anti-P-selectin group showed a significant P-selectin expression, that occurs at the venular bifurcations within 15-30 min of reperfusion, as well as no increase in leukocyte and platelet adhesion on microvessels. BSO partially prevented P-selectin expression but the decrease in capillary perfusion and the increase in both platelet and leukocyte adhesion in microvessels were greater. GSH significantly prevented P-selectin expression as well as capillary perfusion decrease after I/R. In conclusion, GSH inhibition blunted the protective effects of anti-P-selectin treatment with marked leukocyte adhesion on postcapillary venules and platelet-endothelial cell interactions in arterioles and venules and decreased capillary perfusion at reperfusion, thus suggesting that the mechanism of I/R injury is not critically dependent on P-selectin.