Tourniquet-induced acute ischemia–reperfusion injury in mouse skeletal muscles: Involvement of superoxide

Abstract

Although arterial limb tourniquet is one of the first-line treatments to prevent exsanguinating hemorrhage in both civilian pre-hospital and battlefield casualty care, prolonged application of a limb tourniquet can lead to serious ischemia-reperfusion injury. However, the underlying pathomechanisms of tourniquet-induced ischemia-reperfusion injury are still poorly understood. Using a murine model of acute limb ischemia-reperfusion, we investigated if acute limb ischemia-reperfusion injury is mediated by superoxide overproduction and mitochondrial dysfunction. Hind limbs of C57/BL6 mice were subjected to 3 h ischemia and 4 h reperfusion via placement and release of a rubber tourniquet at the greater trochanter. Approximately 40% gastrocnemius muscle suffered infarction in this model. Activities of mitochondrial electron transport chain complexes including complex I, II, III, and IV in gastrocnemius muscle were decreased in the ischemia-reperfusion group compared to sham. Superoxide production was increased while activity of manganese superoxide dismutase (MnSOD, the mitochondria-targeted SOD isoform) was decreased in the ischemia-reperfusion group compared to sham group. Pretreatment with tempol (a SOD mimetic, 50 mg/kg) or co-enzyme Q10 (50 mg/kg) not only decreased the superoxide production, but also reduced the infarct size and normalized mitochondrial dysfunction in the gastrocnemius muscle. Our results suggest that tourniquet-induced skeletal muscle ischemia-reperfusion injuries including infarct size and mitochondrial dysfunction may be mediated via the superoxide over-production and reduced antioxidant activity. In the future, this murine ischemia-reperfusion model can be adapted to mechanistically evaluate anti-ischemic molecules in tourniquet-induced skeletal muscle injury.

Early Therapeutic Intervention for Crush Syndrome: Characterization of Intramuscular Administration of Dexamethasone by Pharmacokinetic and Biochemical Parameters in Rats

“…2, 3), and they suggest a reduction of levels of ROS generated by mitochondrial dysfunction and cellular injury and death in skeletal muscle after ischemia reperfusion. 21) Injection of DEX into crushed muscle resulted in a higher residual drug concentration compared to the other conditions. Therefore, control of local inflammation, indicated by reduced ROS and muscle MPO activity levels, showed beneficial effects.…”

Therapeutic Interventions Against Reperfusion Injury in Skeletal Muscle

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Protective Effects of Sonic Hedgehog Against Ischemia/Reperfusion Injury in Mouse Skeletal Muscle via AKT/mTOR/p70S6K Signaling

“…During the pre-ischemic, ischemic, and initial 3 hours of reperfusion intervals, mice were placed on a heating pad to maintain body temperature at 37°C [14]. Tourniquet-induced I/R injury was identified by measuring blood flow to the gastrocnemius muscle as described previously [15, 16]. Blood flow dropped to approximately 2 % of baseline after placement of the tourniquet and remained at a steady level during the 3 hours of ischemia.…”