A Langendorff-perfused Mouse Heart Model for Delayed Remote Limb Ischemic Preconditioning Studies

Remote ischemic preconditioning (rIPC) through transient limb ischemia induces potent cardioprotection against ischemia reperfusion (IR) injury. I examined the delayed phase of protection that appears 24 hours after the initial rIPC stimulus. The primary objective of this study was to establish a mode of sedation and control treatment for delayed rIPC experiments. I used an ex-vivo, Langendorff isolated-mouse heart preparation of IR injury to examine the delayed effects of an intra-peritoneal (IP) injection, sodium-pentobarbital (SP), halothane and nitrous oxide (N2O) anesthesia on post-ischemic cardiac function. Each anesthetic method improved left-ventricular function after IR injury. SP and halothane anesthesia also reduced LV infarct size. Delayed cardioprotection after IP injections was associated with an increase in phosphorylated-Akt levels. The present study shows that IP injections and inhalational anesthesia invoke cardioprotection and, therefore, indicates that these modes of sedation should not be used as control treatments for studies examining the delayed rIPC phenotype.MAS