Protective effects of norepinephrine preconditioning on myocardial cell during heart cold preservation in rat

【Objective】To investigate the synthesis of heat shock protein 70 (HSP70) induced by norepinephrine preconditioning on donor heart and its protection during heart cold preservation in rat, and investigate the possible mechanism of the protection of this preconditioning. 【Methods】20 Wistar rats were randomly divided into 2 groups with 10 in each group.The rats in the control group were intraperitoneally injected with 0.5 mL saline and 24 hours later isolated hearts were stored with histidine-tryptophan-ketoglutarate (HTK) solution at 4 ℃ for 3 hours to estab-lish Langendorff isolated heart models , and then isolated hearts were perfused by Langendorff model with Krebs-Henseleit (K-H) solution for 10 minute. The rats in the experimental group received intraperitoneally 3.1 μmol/kg (0.53 mg/kg) noradrenaline bitartrate that was dissolved in saline and 24 hours later isolated hearts were stored. Fol- lowed process was the same as that in the control group.Myocardial HSP70 content、myocardial creatine kinase (lac-tate dehydrogenase) 10 min leakage rate and myocardial water content(MWC) were measured, the light and electron microscope structure were observed. 【Results】HSP70 in the experimental group are higher than those in the control group and biochemical indicators in the experimental group are better than those in the control group. There were alleviated ultrastructure injures in the experimental group as compared with those in the control group. 【Conclusions】This study demonstrates that norepinephrine preconditioning can induce the high expression of HSP70 and it can protect heart from cold preservation.The high expression of HSP70 induced by norepinephrine preconditioning maybe the possible mechanism of its protection during heart cold preservation in rat.