Administration of tourniquet. II. Prevention of postischemic oxidative stress can reduce muscle edema.

An experimental group of mice were subjected to a hindlimb tourniquet for 90 min followed by 60 min postischemic reperfusion (ischemia/reperfusion, I/R). Two further groups with the same experimental procedure received allopurinol to inhibit endothelial xanthine oxidase to produce oxygen free radicals (I/R-allo) or vitamin E as a radical scavenger (I/R-vitE). The soleus muscle was examined, and the contralateral muscle served as control. Glutathione (both reduced and oxidized forms, GSH and GSSG) concentrations and the relative protein content were measured. Additionally, the muscles were examined under the electron microscope for pathological alterations. The results showed: (i) the existence of much oxidative stress in the I/R group, but not in the I/R-allo and I/R-vitE groups; (ii) an increased protein content indicative for high capillary permeability in the I/R group, but not in the I/R-allo and I/R-vitE groups; (iii) considerably fewer capillary endothelial disturbances in the I/R-allo and I/R-vitE groups than in the I/R group. We conclude that allopurinol and vitamin E diminished the occurrence of oxidative stress and of edema in postischemic skeletal muscle.