Janus激酶-信号转导子与转录激活子信号通路在硫化氢后处理离体缺血再灌注大鼠心肌中的作用

Role of JAK2/STAT3 signaling pathway in hydrogen sulfide postconditioning on isolated ischemia/reperfusion rat hearts

目的探讨Janus激酶-信号转导子与转录激活子(JAK2/STAT3)信号通路在硫化氢(H2S)后处理减轻离体大鼠心脏缺血/再灌注(I/R)损伤的作用。方法应用Langendorff离体心脏灌流装置、通过停灌30 min/复灌60 min的方法建立SD大鼠I/R模型。按照处理及再灌注成分分为持续灌注对照组,I/R组,NaHS 10μmo.lL-1组,NaHS+AG490 10μmol.L-1组,AG490组和DMSO组。持续测定心率(HR)、左心室形成压(LVDP)、左心室舒张末压(LVEDP)、左室内压上升最大速率(+dp/dtmax)、左室内压下降最大速率(-dp/dtmax);再灌注末取心肌TTC法测心肌梗死面积,TUNEL法测心肌细胞凋亡率,Western印迹法半定量测P-STAT3和总的STAT3表达水平。结果平衡灌注末各组间心功能指标无统计学差异。再灌注后,与I/R组比较,NaHS组明显改善再灌注损伤心功能的各项指标(P<0.05),减少心肌梗死面积〔(23±4)%vs(41±5)%〕(P<0.05);并降低凋亡指数〔(22±4)%vs(43±5)%〕(P<0.05),P-STAT3表达水平明显升高〔(0.0450±0.0034)vs(0.0238±0.0021)〕(P<0.05)。AG490逆转了H2S后处理产生的心肌保护效应及P-STAT3表达水平的增加(P<0.05)。结论 JAK2/STAT3信号通路参与了H2S减轻离体大鼠心脏I/R损伤过程。

OBJECTIVE To investigate whether JAK2/STAT3 signaling pathway participated in hydrogen sulfide postconditioning protecting isolated rat hearts against ischemia/reperfusion（I/R） injury.METHODS Isolated perfused rat hearts were exposed to ischemia 30 min followed by reperfusion for 60 min to establish a rat I/R model using Langendorff apparatus.According to the different experimental protocols,SD rats were randomly assigned to the following groups：control,I/R,NaHS 10 μmol·L-1,NaHS＋AG490 10 μmol·L-1,AG490 and DMSO groups.Left ventricular hemodynamics including the heart rate（HR）,left ventricular developed pressure（LVDP）,left ventricular end-diastolic pressure（LVEDP）,the maximum rate of increase or decrease of left ventricular pressure（±dp/dtmax）were recorded at 20 min after equilibrium,at 30 min after reperfusion and at the end of reperfusion respectively.Myocardial infarct size was determined using triphenyltetrazolium chloride（TTC） staining.Myocardial TUNEL staining was determined by in situ cell death detection kit.The ratio of TUNEL positive nuclei to all the nuclei counted was used as apoptotic index（AI）.The expression of phosphorylation of STAT3（P-STAT3） and total STAT3 was determined with Western blotting analysis at the end of reperfusion.RESULTS No difference in baseline hemodynamics was observed among the experimental groups.After reperfusion,compared with I/R group,NaHS group significantly improved functional recovery and largely decreased myocardial infarct size（（23±4）% vs（41±5）%）（P0.05） and cardiocyte apoptotic index（（22±4）% vs（43±5）%）（P0.05）.Meanwhile,P-STAT3 expression was much higher（（0.0450±0.0034） vs（0.0238±0.0021））（P0.05）.However,AG-490 abolished the cardioprotection offered by hydrogen sulfide postconditioning and increase in P-STAT3 expression.CONCLUSION Hydrogen sulfide postconditioning effectively protects isolated ischemia and reperfusion rat hearts via activating JAK2/STAT3 signaling pathway.