延迟相缺血预处理心肌保护作用耐受现象的探讨

Study about the tolerance phenomenon in the late phase of ischemic preconditioning

关键词:  缺血预处理，心肌  心肌梗死  耐受现象

Key words:  ischemic preconditioning, myocardium  myocardial infarction  tolerance phenomenon

摘要:

［目的］探讨延迟相缺血预处理（ischemic preconditioning,IP）是否存在耐受现象。［方法］新西兰大白兔50只分6组，单纯缺血再灌注组（对照组）8只、缺血预处理组10只；分别间隔不同时间行3次预处理，末次预处理24 h后缺血再灌注，根据间隔时间分为IP 12、18、24和48 h 4组，每组各8只。测量血流动力学指标、心肌梗死面积和心律失常情况。［结果］血流动力学指标组间比较差异无统计学意义。缺血预处理组和4组间隔不同时间预处理组的心梗面积和心律失常发生率均低于对照组（P<0.05）。IP 12 h组的梗死面积和心律失常高于缺血预处理组（P<0.05）。间隔12～24 h，心肌保护作用有增强趋势，而间隔24～48 h保护作用反而减弱，但统计学上差异无显著性意义。［结论］间隔12～48 h的多次延迟相预处理并未产生耐受现象，最佳预处理的时间间隔可能在24 h。

Abstract:

［Objective］ To explore whether the late phase of ischemic preconditioning process the tolerance phenomenon (IP).［Methods］ Fifty New Zealand white rabbits were divided into 6 groups: the group of ischemia and reperfusion (control, 8 rabbits), ischemic preconditioning (10 rabbits) and four additional groups which were preconditioned 4 times according to different time interval, including the group of IP 12, 18, 24 h, and IP 48 h, 8 rabbits in each group. After 24 hours of the last preconditioning, the preconditioned rabbits received ischemia reperfusion models. Data of hemodynamics, myocardial infarct size, and arrhythmia were determined. ［Results］ There was no difference of hemodynamic data among the groups. The infarction size and the incidence of arrhythmia were less in the group of ischemic preconditioning and four additional preconditioned groups than those of control (P<0.05). The group of IP 12 h had larger infarct size and higher incidence of arrhythmia compared with the group of ischemic preconditioning (P<0.05). Even it didn’t reach statistical significance, myocardial protective effects showed increasing trends from the time interval from 12 to 24 hours. It presented inverse trend from the time interval from 24 to 48 hours.［Conclusions］ Multiple late phase of preconditioning with the time interval between 12 to 48 hours doesn't produce the tolerance phenomenon. The best time interval of preconditioning is 24 hours possibly.