Protective Effect of Ischemic Preconditioning on Rabbit Skeletal Muscle

Ischemic preconditioning (IP), a brief period of flow interruption prior to a prolonged ischemic period, increases tolerance to ischemia and improves function during reperfusion in the heart. The aim of the present study is to determine whether IP attenuates and protects against ischemia-reperfusion injury in the skeletal muscle of rabbits. Normal sham control (NC) group was the leg muscles which had no procedures taken after anesthesia. Ischemic control (ICH) group was the leg muscles with ischemia taken for 180 min. followed by reperfusion for 60 min, after anesthesia. Ischemic preconditioning 1 (IP 1) group, IP 2 group and IP 3 group were the leg muscles taken 1, 2 and 3 cycles of ischemia for 10 min. and reperfusion for 10 min. respectively, prior to same procedures as ICH group. The ischemic injury of skeletal muscles was assessed using transmission electron microscope and biospectrophotometric method. The triphenyltetrazolium chloride (TTC) reduction activity was measured, and concentrations of the ATP and its metabolites were also measured. The ICH group showed severe to irreversible changes of the myocytes homogenousely in contrast to the IP 1 group in which irreversible change was only focal and not homogenous. The TTC reduction assay significantly demonstrated that the IP 1 and IP 2 group showed higher reduction activity than the ICH group (p<0.05). The ATP content of muscles was maintained higher in the IP 1 group than in the ICH group (P<0.05). The protective effect of ischemic preconditioning can be induced in the rabbit skeletal muscles, and its effect is associated with lower energy metabolism during sustained ischemia.