外源性硫化氢后处理对离体大鼠心肌细胞凋亡及Bcl-2、Bax蛋白表达的影响

目的探讨硫化氢（H2S）后处理对离体大鼠心肌缺血/再灌注（ischemia-reperfusion,I/R）损伤后心肌细胞凋亡的影响及与Bcl-2、Bax蛋白表达的关系。方法 42只雄性SD大鼠随即分为3组（n=14）：sham组、I/R组、H2S后处理组（N组）。采用离体心脏Langendorff灌注模型,平衡灌注20 min后停灌40 min复灌60 min。记录平衡末及灌注结束时的左室舒张压（LVEDP）、左室发展压（LVDP）、左室内压上升最大速率（＋dp/dt）、左室内压下降最大速率（-dp/dt）、心率（HR）、冠状动脉血流量（CF）;灌注结束时,TTC法染色计算心肌梗死面积百分比,TUNEL法检测心肌细胞凋亡计算凋亡指数（AI）,Western blot半定量Bcl-2、Bax蛋白表达水平。结果平衡灌注末各组间心功能指标（基础值）差异无统计学意义（P〉0.05）。灌注结束时,与I/R组比较,N组可改善再灌注损伤心功能的各项指标（P〈0.05）,使心肌梗死面积缩小和AI降低（P〈0.05）,Bcl-2蛋白表达水平升高,Bax蛋白表达水平降低（P〈0.05）。结论外源性H2S后处理通过调控Bcl-2与Bax表达减轻离体大鼠心肌缺血/再灌注时心肌细胞凋亡的发生。

The effect of exogenous hydrogen sulfide postconditioning on myocarial apoptosis and expression of Bcl-2 and Bax protein following ischemia and reperfusion in isolated rat hearts

Objective To investigate the effects of hydrogen sulfide postconditioning on myocardial cell apoptosis following ischemia-reperfusion（I/R） and its relationship with the expressions of Bcl-2 and Bax protein in isolated rat hearts.Methods 42 male SD rat hearts were randomly divided into 3 groups（n=14）： sham group,I/R group;hydrogen sulfide postconditioning group（N group）.Langendorff isolated rat heart perfusion model was established,followed by equilibrium perfusion for 20 min,40 min of pause and subsequent reperfusion for 60 min.The left ventricular diastolic pressure（LVEDP）,left ventricular developed pressure（LVDP）,the maximum rate of increase or decrease of left ventricular pressure（±dp/dtmax）,heart rate（HR）,coronary flow（CF） were recorded at 20 min of equilibrium and 60 min of reperfusion,respectively.At the end of perfusion（20 min）,the percentage of myocardial infarct area was measured using triphenyltetrazolium chloride（TTC） staining.The myocardial apoptosis was detected by TUNEL assay to calculate apoptotic index（AI）.The semi-quantitative expression of Bcl-2 and Bax was determined with Western blot at the end of reperfusion.Results At the end of equilibrium perfusion,there were no statistical differences in baseline hemodyamics between the experimental groups（P0.05）.At the end of reperfusion,compared with I/R group,N group improved hemodynamic injury induced by the I/R（P0.05） and significantly increased the expression of Bcl-2,and greatly decreased the expression of Bax（P0.05）.Conclusion Exogenous hydrogen sulfide postconditioning effectively protects isolated rat hearts against ischemia-reperfusion injury by modulating Bcl-2 family proteins.