Myocardial protection provided by chronic skeletal muscle ischemia is not further enhanced by ischemic pre- or postconditioning: comparative effects on intracellular signaling.

Chronic skeletal muscle ischemia protects the ischemic heart by preserving coronary flow and inducing arterioangiogenesis. We sought to determine the effect and the underlying molecular mechanisms of preconditioning (PreC) and postconditioning (PostC), applied in a model of chronic skeletal muscle ischemia. Male rabbits were divided into 3 series. In each series, the animals were subjected either to severe hind limb (HL) ischemia, by excision of the femoral artery, or to sham operation (SHO). After 4 weeks, all the animals underwent 30 minutes of regional heart ischemia and 3 hours reperfusion. The animals of the first series received no further intervention (HL and SHO groups), those of the second series underwent PreC (HL + PreC and SHO + PreC), and of the third series PostC (HL + PostC and SHO + PostC). Infarct size (I) and risk zones (R) were determined, and their ratio was calculated in percentage. Three additional series of experiments were performed with respective interventions up to the 10th minu...