[Ischemic preconditioning improves postischemic function, but not energy metabolism of skeletal muscles]

Ischemic preconditioning (IP) refers to a phenomenon whereby short periods of ischemia reduce tissue damage after a subsequent sustained ischemia. The effect of IP before tourniquet ischemia of the extremities has not yet been evaluated. We developed a rat model of skeletal muscle ischemia and measured the effect of IP on postischemic function and high-energy phosphate levels. IP consisted in three cycles of 10 min ischemia and 10 min reperfusion each. IP improved significantly skeletal muscle function after 3 hours of ischemia and 2 hours of reperfusion. High-energy phosphate levels, however, remained unchanged. This study is the first that shows a protective effect of IP in skeletal muscles. These results furthermore suggest that the protection of energy metabolism is not a mechanism of IP in this model. IP could be easily performed before surgery of the extremities under tourniquet ischemia. The protective effect on postischemic skeletal muscle has therefore to be further investigated.