Ischemic preconditioning improves post-ischemic skeletal muscle function.

Ischemic preconditioning (IP), using one or more brief periods of ischemia before a sustained ischemia, represents a new approach to reduce tourniquet ischemia-induced skeletal muscle damage. The aim of this study was to investigate the effect of IP on skeletal muscle function and high-energy phosphate tissues levels in a rodent model. IP protocols using one, two, or three preconditioning cycles were compared. IP was found to significantly improve force, performance, endurance, and contractility of postischemic skeletal muscle. The efficacy of IP-induced protection was correlated with the number of preconditioning cycles. Preconditioning with three cycles resulted in a more effective protection as compared to one or two cycles. Three cycles of IP significantly improved force (409 +/- 63 versus 240 +/- 47 mN), performance (2546 +/- 481 versus 1081 +/- 242 mN*sec), endurance (46.7 +/- 5.0 versus 29.6 +/- 3.4 sec) and contractility (59.9 +/- 4.2 versus 38.7 +/- 5.1) in postischemic m.extensor dig. long. when compared to nonpreconditioned muscles. In contrast, high-energy phosphate tissue levels remained unchanged after three cycles of preconditioning. Altogether, this study describes, for the first time, the efficacy of IP to improve postischemic muscle function. The respective clinical potential warrants further exploration.