无创性肢体缺血预适应的早期及延迟效应对中年大鼠心肌缺血再灌注损伤的保护作用和差异

Protective effects against myocardial ischemia-reperfusion injury in middle-aged rats with early vs delayed noninvasive limb ischemic preconditioning

目的研究无创性肢体缺血预适应的早期及延迟效应对中年大鼠心肌缺血再灌注(I/R)损伤的保护作用和差异。方法对预适应组中年大鼠实施1d或连续3d无创性后肢缺血预适应后,分别对其立即实施心脏I/R处理,或24h后再实施心脏I/R处理,与对照组(单纯实施心脏I/R)相比较,观察无创性肢体缺血预适应的早期和延迟效应对中年大鼠心脏I/R后心脏生理学指标[心率(HR)、平均动脉压(MAP)、ST段]、血清学指标、心律失常Lambeth评分、各组I/R后的心肌梗死面积的影响。结果无创性后肢缺血预适应的早期效应组保护效应作用明显。1E,3E组心脏梗死面积(IS/AAR)减小,与对照组IS/AAR[(50±9)%]比较,1E[(15±5)%]和3E[(35±10)%]组IS/AAR显著降低(P<0.05);心律失常Lambeth评分降低,1E[(2.6±0.9)分]、3E[(2.6±1.1)]分组与对照组[(4.2±0.8)分]比较,差异有统计学意义(P<0.05);血清中丙二醛(MDA)的含量减少,血浆中MDA的含量在1E[(7.4±1.2)nmol/ml]、3E[(6.8±0.9)nmol/ml]组中较对照组大鼠[(9.4±1.0)]nmol/ml均显著降低(P<0.05);超氧化物歧化酶(SOD)酶活性增加,血浆中SOD酶活性在1E[(295±30)U/ml]、3E[(345±22)U/ml]组中较对照组大鼠[(257.4±21.0)U/ml]均显著升高(P<0.05,P<0.01);谷胱甘肽过氧化物酶(GSH-PX)酶活性增加,与对照组[(1196±127)U/L]相比,早期预适应组1E[(1547±193)U/L],3E[(1624±69)U/L]组血清中GSH-PX的活性均显著增高(P<0.05)。结论无创性后肢缺血预适应的早期效应对中年大鼠心脏I/R损伤具有保护作用,且其作用大于其延迟效应。

Objective To study the protective effects against myocardial ischemia-repeffusion （I/R） injury in middle-aged rats with early vs delayed noninvasive limb isehemic preconditioning. Methods Noninvasive ischemic preconditioning in right hind limb was given to middle-aged rats （preconditioned groups） for one and three days, respectively, followed by cardiac I/R immediately or after 24 hours. In comparison with the controls （non-preconditioned cardiac UR treatment）, the rats were studied for changes in cardiac physiology （HR, MAP, and ST-segment）, serology, Lambeth arrhythmia score and post-I/R size of myocardial infarction as related to early and delayed effects of noninvasire limb ischemic preconditioning. Results Significant protection against myocardial injury was observed with early limb ischemic preconditioning （both 1E and 3E groups）. Compared with the controls, the 1E and 3E gruups showed smaller sizes of myocardial infarction [IS/AAR, （15-±5）% and （35±10）% vs （50±9）%, P〈0.05], lower Lambeth arrhythmia scores [（2.6±0.9） and （2.6±1.14） vs （4.2±0.8）, P〈0.05], less contents of plasma MDA [（2.6±0.9） nmol/ml and （6.8±0.9） nmol/ml vs （9.4±1.0）nmol/ml, P〈0.05], enhanced plasma SOD activity [（295±30） U/ml and 3E （345±22） U/ml vs （257.49±21.04） U/ml, P〈0.05 and P〈0.01], and enhanced plasma GSH-PX activity [（1547±193） U/L and 3E （1624± 69） U/L vs （1196±127） U/L, P〈0.05]. Conclusion Early right hind limb isehemie preconditioning resulted in more protection against myocardial I/R injury in middle-aged rats as compared greatly to delayed preconditioning.