Local and remote ischemic postconditionings have synergistic protective effects on renal ischemia-reperfusion injury.

I n the current era of meticulous surgical technique and modern immunosuppressive therapy, ischemiareperfusion injury (IRI) is one of the major determinants of early and longterm allograft function after kidney transplantation (1, 2). In an experimental model of renal IRI, we showed that remote ischemic preconditioning using the hind limb as the remote organ is effective in reducing IRI (3). Kadkhodaee et al. (4) recently reported that remote ischemic perconditioning and remote ischemic postconditioning (RIPostC) also significantly reduce renal IRI in a comparable model. Here, we report the first data on the combined effect of local IPostC (LIPostC) and RIPostC on renal IRI. Male Sprague-Dawley rats weighing approximately 300 g were randomized into five groups before surgery. All animals underwent nephrectomy of the left kidney. Five sham-operated animals served as a baseline control (sham). All other animals were subjected to 25 min of renal ischemia (by clamping the renal artery and vein of the right kidney) with 48 hr of reperfusion. Eight animals underwent renal IRI only (no IPostC). In nine animals, three cycles of RIPostC by brief hind limb ischemia were induced directly after clamp release, by inflating small blood pressure cuffs around both proximal thighs for 5 min, followed by 5 min of reperfusion (RIPostC). Successful hind limb occlusion (loss of pulse and strong decrease of saturation) was confirmed by means of a pulse oximeter clip placed on the foot. In another nine animals, LIPostC was induced by six cycles of 8 sec of ischemia, followed by 8 sec of reperfusion (LIPostC). Seven