S-nitroso human serum albumin treatment reduces ischemia/reperfusion injury in skeletal muscle via nitric oxide release

Background-Peroxynitrite generated from nitric oxide (NO) and superoxide (O-2(-)) contributes to ischemia/reperfusion (I/R) injury. Feedback inhibition of endothelial NO synthase by NO may inhibit O-2(-) production generated also by endothelial NO synthase at diminished local L-arginine concentrations accompanying I/R. Methods and Results-During hindlimb I/R (2.5 hours/2 hours), in vivo NO was monitored continuously (porphyrinic sensor), and high-energy phosphates, reduced and oxidized glutathione (chromatography), and I/R injury were measured intermittently. Rabbits receiving human serum albumin (HSA) (controls) were compared with those receiving S-nitroso human serum albumin (S-NO-HSA) beginning 30 minutes before reperfusion for 1 hour or 30 minutes before ischemia for 3.5 hours (0.1 mumol . kg(-1) . h(-1)). The onset of ischemia led to a rapid increase of NO from its basal level (50 +/- 12 nmol/L) to 120+/-20 and 220+/-15 nmol/L in the control and S-NO-HSA-treated groups, respectively. In control animals, NO dropped below basal levels at the end of ischemia and to undetectable levels (<1 nmol/L) during reperfusion. In S-NO-HSA-treated animals, maximal NO levels never decreased below basal concentration and on reperfusion were 100 +/-15 nmol/L (S-NO-HSA preischemia group, 175 +/- 15 nmol/L). NO supplementation by S-NO-HSA led to partial and in the preischemia group to total preservation of high-energy phosphates and glutathione status in reperfused muscle (eg, preischemia groups: ATP, 30.23+/-5.02 μmol/g versus control, 15.75+/-4.33 μmol/g, P<0.0005; % oxidized glutathione, 4.49+/-1.87% versus control, 22.84+/-6.39%, P<0.0001). S-NO-HSA treatment in all groups led to protection from vasoconstriction and reduced edema formation after reperfusion (eg, preischemia groups: interfiber area, 12.94+/-1.36% versus control, 27.83+/-1.95%, P<0.00001). Conclusions-Long-lasting release Of NO by S-NO-HSA provides significant protection of skeletal muscle from I/R injury.