常温缺血预处理对幼兔未成熟心肌的保护作用

Protective Effect of Normothermia Ischemic Preconditioning on Immature Rabbit Myocardium

目的 研究常温缺血预处理 (IP)对幼兔未成熟心肌的保护作用。 方法 将 2 4只幼兔分为四组。组 1:IP 1次 ;组 2 :IP 2次 ;组 3:IP 3次 ;对照组。应用 L angendorff心脏灌注方法 ,对 3～ 4周龄幼兔离体心脏实施不同次数的 5分钟缺血、5分钟再灌注的常温 IP,常温缺血 45分钟 ,再灌注 30分钟。于平衡灌注末、缺血前、再灌注 3分钟、5分钟、10分钟、2 0分钟和 30分钟分别测定左心室发展压 (L VDP)、左心室最大上升及下降速率 (± dp/ dt max) ,再灌注末测定心肌组织三磷酸腺苷 (ATP)含量、丙二醛 (MDA)含量和超氧化物歧化酶 (SOD)活性。 结果 再灌注 30分钟时 ,组 1和组 2 L VDP、+dp/ dtm ax恢复率显著高于对照组 (P<0 .0 5 ,P<0 .0 1) ,组 3L VDP、± dp/ dt max的恢复率与对照组比较差别无显著性意义。再灌注末组 1、组 2和组 3心肌 ATP含量显著高于对照组 (P<0 .0 5 )。组 2 MDA含量显著低于组 1、组 3和对照组 (P<0 .0 5 )。 结论 IP对未成熟心肌具有保护作用 ,其中 2次 IP的保护作用最好 ,而 3次的保护作用减弱 ,表明

Objective To determine the protective effect of normothermia ischemic preconditioning (IP) on immature myocardium. Methods Twenty four rabbits were divided into four groups randomly.Group 1 :one time IP, group 2:two times IP, group 3:three times IP, and control group. Isolated neonatal rabbit hearts were subjected to different periods of normothermia IP and then followed by 37℃,45 minutes of ischemia and 30 minutes of reperfusion in Langendorff mode. Determinations of left ventricular developed pressure (LVDP), positive and negative peak first derivative (±dp/dt max) by the end of balanced perfusion, before ischemia and 3min,5min,10min,20min,30min after reperfusion, and contents of adenosine triphosphate (ATP) and malondialdehyde (MDA), as well as activity of super oxide dismutase (SOD) at the end of reperfusion were also completed. Results The results demonstrated that recoveries of LVDP, +dp/dt max in group 1 and group 2 were significantly better than those in control group( P <0.05, P <0.01). The contents of ATP for group 1,group 2 and group 3 were also higher in comparison with control group( P < 0.05). MDA in group 2 was lower than that in other three groups ( P <0.05). Conclusion The normothermia IP can remarkably enhance immature rabbit myocardial protection. The best protective result is found in two times of IP while a three times of IP does not show satisfactory myocardial protection. Obviously, there are accumulative phenomenon and saturated effect with regard to IP on immature myocardium.