Nitric oxide has been reported to be beneficial in preserving muscle viability following
ischemia-reperfusion injury. The purpose of this study was to evaluate the influence of
nitric oxide via
L-arginine on leukocyte adhesion following
ischemia-reperfusion injury. Intravital videomicroscopy of rat gracilis muscle was used to quantify changes in leukocyte adherence. The gracilis muscle was raised on its vascular pedicle in 48 male Wistar rats. The animals were assigned to one of five groups: (1) nonischemic control; (2)
ischemia-reperfusion; (3)
ischemia-reperfusion and
L-arginine; (4)
ischemia-reperfusion and Nomega-nitro-
L-arginine methyl ester (
L-NAME); and (5)
ischemia-reperfusion,
L-NAME, and
L-arginine. All groups that included
ischemia-reperfusion were subjected to 4 hours of global
ischemia followed by 2 hours of reperfusion.
L-Arginine (10 mg/kg) and
L-NAME (10 mg/kg) were infused into the contralateral femoral vein beginning 5 minutes before reperfusion, for a total of 30 minutes. The number of adherent leukocytes was counted at baseline and at 5, 15, 30, 60, and 120 minutes after reperfusion (reported as mean change from baseline, +/- SEM). Groups were compared by repeated-measures analysis of variance (five groups, five times). P < or =0.05 was accepted as significant.
L-Arginine significantly reduced leukocyte adherence to venular endothelium during reperfusion when compared with the
ischemia-reperfusion group (1.39 +/- 0.92 versus 12.78 +/- 1.43 at 2 hours, p < 0.05). Administration of
L-NAME with
L-arginine showed no significant difference in adherent leukocytes when compared with the
ischemia-reperfusion group (10.28 +/- 2.03 at 2 hours). The
nitric oxide substrate
L-arginine appears to reduce the deleterious neutrophil-endothelial adhesion associated with
ischemia-reperfusion injury.
L-NAME (
nitric oxide synthesis inhibitor) given concomitantly with
L-arginine reversed the beneficial effect of
L-arginine alone, indicating that
L-arginine may be acting via a
nitric oxide synthase pathway. These results suggest an important role for
nitric oxide in decreasing the neutrophil-endothelial interaction associated with
ischemia-reperfusion injury.