腺苷及缺血预调对未成熟兔心肌乳酸代谢及心肌耗氧的影响及意义

Effects of Adenosine and Preconditioning Ischemia on Lactate Metabolism and Myocardial Oxygen Consumption in Immature Rabbits

目的 研究腺苷及缺血预调 (IPC)对未成熟新西兰兔心肌乳酸代谢及心肌耗氧的影响 ,探讨其机制。方法 利用改良 L angendǒrff- Neely体外心脏灌流法建立工作心模型。对照组未作预处理 ,缺血期间仅间断心脏停搏液灌注 ;IPC组停搏液灌注前行缺血预调 ;腺苷强化缺血预处理 (APC)组缺血预调前予以冠脉内注入腺苷 ;腺苷预处理 (ADO)组停搏液灌注前予以冠脉内注入腺苷。以左室功能恢复、心肌耗氧量 (MVO2 )、乳酸 (L ac)产量、心肌含水量 (MWC)、心肌组织腺核苷总量 (TAN)和丙二醛 (MDA)含量作为观察指标。 结果 缺血后再灌注 ,APC组左室功能恢复最佳 ,MWC最低 ,TAN含量最高 ,MDA含量最低 ;IPC、APC组 MVO2 的恢复率均高于其他二组 ,对照组 L ac产量明显高于其他三组。 结论 缺血预调前加用腺苷能明显改善再灌注期未成熟兔心肌的氧耗 ,减少乳酸产量 。

Objective\ To investigated effects of adenosine and preconditioning ischemia on lactate metabolism and myocardial oxygen consumption in immature rabbit hearts.Methods\ On an isolated working heart model.\ Control group(CON, n=10) received intermittent cold cardioplegia perfusion.\ Ischemic preconditioning group(IPC, n=10) received 5 minutes of global ischemia and 5 minutes of reperfusion before cold cardioplegia perfusion.\ Adenosine\|enhanced ischemic preconditioning group(APC, n=10) received an intracoronary bolus injection of adenosine at the immediate start of ischemic preconditioning.\ To separate the effects of adenosine from that of APC, a control group(ADO, n=10) received an intracoronary bolus injection of adenosine 10 minutes before global ischemia.\ Myocardial protective effects were mainly assessed by the recovery of left ventricular function, myocardial oxygen consumption(MVO\-2), lactate output, myocardial water content(MWC), myocardial total adenosine nucleotides and malonaldehyde(MDA).\ Results\ During reperfusion,the recovery of left ventricular function of APC group were significantly improved, myocardial water content lessen obviously less, myocardial total adenosine nucleotides content significantly higher and MDA content lower.\ The recovery of MVO\-2 of IPC and APC groups were higher than two other groups.\ The lactate output was highest in CON group.\ \{Conclusion\}\ These results suggest adenosine pretreated before ischemic preconditioning ameliorate oxygen consumption, reduce the lactate levels and promote function recovery of immature rabbit heart during reperfusion.