Ischemic preconditioning: Lack of delayed protection against skeletal muscle ischemia-reperfusion

We investigated the ability of ischemic preconditioning to induce expressio n of heat shock protein 70 (Hsp 70) and/or to increase muscle survival afte r ischemia-reperfusion in the rat hind limb. Ischemic preconditioning regim ens tested were; 1 x 5 min of ischemia, 4 x 5 min of ischemia interrupted b y 10 min of reperfusion, 1 x 10 min of ischemia or 2 x 10 min of ischemia i nterrupted by 15 min of reperfusion. Western blot analysis revealed only a modest induction of Hsp 70 at 24 h after preconditioning using the latter t wo protocols of 1 x 10 min of ischemia or 2 x 10 min. Used at 24 h prior to prolonged ischemia, neither protocol improved muscle survival measured at 24 h after reperfusion, In conclusion, ischemic preconditioning did not pro duce delayed protection from ischemia-reperfusion in this model and the stu dy suggests that ischemic preconditioning is not a useful protective strate gy against skeletal muscle necrosis in the long-term. (C) 2000 Wiley-Liss, Inc.