Heparinization reduces endothelial permeability and hydrogen ion accumulation in a canine skeletal muscle...

Skeletal muscle injury after revascularization (ischemia-reperfusion) continues to be a major clinical problem. Although heparinization has been recommended, its action in an experimental model of I-R has not been evaluated. We investigated the ability of heparinization to decrease I-R injury in 10 anesthetized dogs (nonheparinized, n = 5; heparinized, n = 5), subjecting one gracilis muscle to 6 hours of ischemia followed by 1 hour of reperfusion while the identically prepared contralateral muscle served as a nonischemic control. Skeletal muscle infarction was determined by Tc-PYP uptake. Endothelial permeability was quantified by measurement of skeletal muscle 125I-Alb activity after intravenous injection. Interstitial hydrogen ion (H+) accumulation was determined by a miniature pH electrode inserted into the gracilis muscle. Isotopic activities from the ischemic muscle were calculated as a percentage of the contralateral nonischemic muscle (mean +/- SEM). Nonheparinized ischemic muscles had an increase in the activities of Tc-PYP and 125I-Alb of 684% +/- 149% and 742% +/- 130%, which were reduced to 218% +/- 54% and 378% +/- 85% by heparinization, respectively (p less than 0.05). During ischemia, the nonheparinized muscles accumulated 1223 +/- 121 nmol of H+ compared with 785 +/- 95 nmol in the heparinized animals (p less than 0.01). This significant reduction in I-R injury may be causally related to diminished endothelial permeability and H+ accumulation.