超声斑点追踪成像评价缺血后适应对兔心肌再灌注损伤的保护作用

Evaluation of protect effects of ischemia postconditioning on myocardial reperfusion injury using ultrasound speckle tracking imaging

目的采用超声斑点追踪成像（STI）评价兔心肌缺血再灌注模型左室心功能变化，探讨缺血后适应对心肌功能的保护作用。方法健康日本大耳白兔24只随机分为2组：组I，单纯缺血再灌注组；组Ⅱ，缺血后适应组。采用STI评价两组兔冠状动脉阻断前后及再灌注前后左室应变及扭转功能变化特征，与病理学结果比较。结果①阻断后，两组整体纵向收缩期应变率（GLSrsys）、整体纵向收缩期应变（GLSsys）和整体纵向峰值应变（GLSp）降低；左室侧壁局部纵向收缩期应变率（SrLsys）、纵向收缩期应变（SLsys）和纵向峰值应变（SLp）明显降低，纵向等容舒张期应变率（SrLivr）负向峰值增高，收缩后应变指数（PSI）明显增大；左室扭转角度峰值（Ptw）和解旋率（untwR）明显降低；②再灌注后，组1IGLSp增大；组I各整体应变指标无明显变化，两组问各指标无明显差异；组lISrLsys、SLsys和SLp明显升高，SrLivr负向峰值明显降低，PSI值降低，组ISLsys、SLp升高；组间比较，组1ISrLsys、SLp较组I高（P〈0．05或0．01），SrI．ivr降低（P〈0．05）；组ⅡPtw和untwR明显大于组I（P〈0．05）；③GLSrsys、GLSsys、SrLsys、SI。sys和Ptw检测兔心肌梗死模型的敏感性和特异性分别为81．3％和75．0％、62．5％和81．2％、87．5％和87．5％、93．8％和75．0％、81．3％和68．7％。结论STI能够准确评价兔左室心肌功能变化，准确检测缺血后适应对心肌再灌注损伤的保护效应，敏感性高。

[Abstract] Objective To evaluate left ventricular myocardial function of rabbit after ischemiareperfusion using speckle tracking imaging （STI）,and to explore the myocardial protect effects of isehemia postconditioning （I-PostC） on reperfusion injury. Methods 24 Japanese rabbits were divided into ischemiareperfusion group （group I ） and I-PostC group （groupⅡ） randomly. The characteristic changes of left ventricular global and regional myocardial strain and twist function of two groups were evaluated quantitatively by ST1 and compared with pathological results. Results Global longitudinal systolic strain rate（GLSrsys）, global longitudinal systolic strain（GLSsys） and global longitudinal peak strain（GLSp） decreased in both groups, longitudinal systolic strain rate （SrLsys）, longitudinal systolic strain （SLsys） and longitudinal peak strain（SLp） in the lateral wall of left ventricle decreased significantly and negative peak of SrLivr and PSI increased after the left ventricular branch of coronary artery was occluded The values of Ptw and untwR of left ventricle were smaller. After the artery was released, GLSp recovered in group Ⅱ , which was not seen in group The values of SrLsys,SLsys and SLp increased significantly and negative peak of SrLivr and PSI decreased in group Ⅲ. However,only Slsys and SLp rebounded in group Ⅰ Between the 2 groups,SrLsys andSLp in group H were higher than that of group I （ P 〈0.05 or 0.01） ,and SrLivr was lower compared with group Ⅰ （ P 〈0.05）. In group Ⅲ , Ptw and untwR changed back to a normal range （ P 〈0.05 or 0.01） ,and no index has changed in group l ;Between the 2 groups,Ptw and untwR ingroup Ⅱ were higher than that of group I （ P〈 0. 05）. The sensitivity and specificity of GLSrsys, GLSsys, SrLsys, SLsys and Ptw to detect rabbit myocardial infarction were 81.3 % and 75.0%,62.5 % and 81. 2% ,87. 5% and 87.5%,93.8M and 75.0%,81.3% and 68.7% respectively. Conclusions STI may provide a promising approach to evaluate the global and regional myocardial function. It also can observe the protect effects of I-PostC on myocardial reperfusion injury accurately.