地尔硫䓬对离体大鼠心肌缺血再灌注损伤影响的研究

目的探讨地尔硫䓬对离体大鼠心肌缺血再灌注损伤的影响及其机制。 方法33只大鼠随机分为3组：正常对照组（N组）、缺血再灌注组（I-R组）、地尔硫䓬＋缺血再灌注组（D/I-R组）。N组持续灌流K-H液150 min；I-R组K-H液稳定灌流30 min后，结扎前降支30 min，继以K-H液再灌注90 min；D/I-R组给予地尔硫䓬（5 μmo/L）再灌注15 min，继以K-H液再灌流75 min。记录并分析各组大鼠左心室发展压、左心室内压力最大上升/下降速率（±dp/dtmax）、再灌注心律失常评分、心肌梗死面积以及各组左心室心尖组织的线粒体乙醛脱氢酶2（ALDH2）、Bcl-2以及Bax的mRNA基因与蛋白表达水平。 结果（1）左心室发展压D/I-R组再灌注30 min与45 min比I-R组压力明显升高［（92.68±5.09）mmHg vs（75.77±5.33）mmHg；（90.39±4.29）mmHg vs（72.34±7.49）mmHg；1 mmHg=0.133 kPa］，差异均具有统计学意义（F=72.81、51.92，P均=0.001）。（2）±dp/dtmax D/I-R组再灌注30 min与45 min时均比I-R组升高［＋dp/dtmax：（2885.45±286.47）mmHg vs （2063.64±105.57）mmHg；（2712.73±236.52）mmHg vs（2053.64±92.33）mmHg；-dp/dtmax：（2214.55±104.63）mmHg vs （1710.91±217.97）mmHg；（2119.09±84.43）mmHg vs（1544.55±207.72）mmHg］，差异均具有统计学意义（F=64.22、70.55、69.77、54.64，P均=0.001）。（3）N组仅有室性期前收缩的发生，未发生心室颤动、室性心动过速；D/I-R组出现室性期前收缩的个数较N组增加，差异具有统计学意义（P=0.001）；I-R组室性心动过速发生率高于D/I-R组，心室颤动时程与室性心动过速时程均较D/I-R组增加，差异具有统计学意义（P=0.013、0.049、0.001）；再灌注心律失常评分I-R组评分［5（3，6），57.36］高于D/I-R组［3（1，4），34.77］，差异具有统计学意义（P=0.001）。（4）心肌梗死面积I-R组高于D/I-R组［（55.51±1.43）% vs （17.01±1.13）%］，差异具有统计学意义（P<0.01）。（5）I-R组线粒体ALDH2表达明显减少。D/I-R组线粒体ALDH2表达与I-R组比较减少，但差异无统计学意义（P=0.11），Bcl-2、Bax的表达均增加，D/I-R组Bcl-2/Bax的比值较I-R组增大（0.44 vs 0.22），差异具有统计学意义（P=0.001）。 结论地尔硫䓬处理后能够减少缺血再灌注损伤。其保护作用机制之一可能是通过上调Bcl-2下调Bax的基因和蛋白表达，减少心肌细胞的凋亡，但其并不是通过上调线粒体ALDH2的基因与蛋白来实现。

Effect of diltiazem on myocardial ischemia-reperfusion injury in isolated rat hearts

ObjectiveTo investigate the effects of diltiazem on myocardial ischemia-reperfusion injury (MIRI) and the underlying mechanisms. MethodsWistar rats were randomly divided into three groups: normal group (N group), ischemia-reperfusion group (I-R group), diltiazem+ ischemia-reperfusion group (D/I-R group). The isolated rat hearts in different groups were given different perfusion treatments: The N group was given continuous perfusion of K-H liquid for 150 min; the I-R group was given stable perfusion of K-H liquid for 30 min followed by ligating the left anterior descending coronary artery for 30 min, and K-H liquid reperfusion for 90 min; the D/I-R group underwent reperfusion with diltiazem (5 μmo/L) for 15 min and reperfusion with K-H liquid for 75 min. Left ventricular cardiac function (LVDP), maximal rise/fall rate of left ventricular pressure (±dp/dtmax), reperfusion arrhythmia (RA) score, calculated myocardial infarct (MI) size, and ALDH2, Bcl-2, and BAX expression in the left ventricular apex were recorded in each group. ResultsThe LVDP at 30 min and 45 min in the D/I-R group was significantly higher than that of the I-R group, respectively (92.68±5.09) mmHg vs (75.77±5.33) mmHg, F=72.81, P=0.001; (90.39±4.29) mmHg vs (72.34±7.49) mmHg, F=51.92, P=0.001]. The ±dp/dtmax at 30 min and 45 min in the D/I-R group were significantly higher than that of the I-R group, respectively + dp/dtmax: (2885.45±286.47) mmHg vs (2063.64±105.57) mmHg, F=64.22, P=0.001 and (2712.73±236.52) mmHg vs (2053.64±92.33) mmHg, F=70.55, P=0.001; -dp/dtmax: (2214.55±104.63) mmHg vs (1710.91±217.97) mmHg, F=69.77, P=0.001 and (2119.09±84.43) mmHg vs (1544.55±207.72) mmHg, F=54.64, P=0.001, respectively]. The number of ventricular pre-contractions in the I-R group was significantly higher than that of the D/I-R group (P=0.001). The incidence of ventricular tachycardia, the time history of ventricular fibrillation, and the duration of ventricular tachycardia in the I-R group were also significantly higher than those of the D/I-R group (P=0.013, 0.049, and 0.001, respectively). The reperfusion arrhythmia score in the I-R group 5(3, 6), 57.36] was significantly higher than that of the D/I-R group 3(1, 4), 34.77] (P=0.001). Compared with the I-R group, the D/IR group had significantly smaller MI size (55.51±1.43)% vs (17.01±1.13)%, P<0.01]. In the I-R group, the expression of mitochondrial ALDH2 was significantly reduced and that of Bcl-2 and Bax increased. Compared with the I-R group, the expression of mitochondrial ALDH2 was not significantly decreased in the D/IR group (P=0.11), while the expression of Bcl-2 and Bax was significantly increased. Compared with the I-R group, the D/I-R group had significantly increased Bcl-2/Bax ratio (0.44 vs 0.22, P=0.001). ConclusionDiltiazem reduces MIRI possibly by up-regulating the expression of mitochondrial Bcl-2 and down-regulating the expression of Bax. However, the therapeutic effect of diltiazem is not related with the gene and protein expression of mitochondrial ALDH2.