RISK途径在二氮嗪后处理离体大鼠心肌中的保护作用

摘要

Aim To discuss whether specific mitochon-drial ATP-sensitive potassium channel opener diazoxide ( DZ ) postconditioning activates RISK signaling path-way to protect isolated rat hearts against ischemica reperfusion injury ( IRI ) . Methods Langendorff de-vice was used to establish rat in vitro model of myocar-dial ischemia reperfusion. SD rats were randomly di-vided into normal group ( NOR ) , control group ( CON ) , diazoxide after treatment group ( DZ ) , and LY294002 antagonistic nitrogen Triazine group ( DZ +LY) , with 8 cases in each. The following was com-pared:①whether heart function of each group changed at the end of equilibration and reperfusion; ② at the end of myocardial perfusion and separation, protein was extracted, and protein kinase B ( PKB / Akt ) , P70S6 kinase (P70S6K), endothelial nitric oxide syn-thase ( eNOS) phosphorylation level of expression were analysed by Western blot. Results ① Indicators of changes in heart function: for DZ group at the end of reperfusion , HR , CF , LVDP , LVEDP , +d p/d tmax and -dp/dtmax were significantly better than those in CON group and DZ + LY group ( P <0.01 ) , but worse than those in NOR group ( P <0.01 ); there was no statistical difference in cardioac function at the end of equilibration. ② For DZ group at the end of reperfu-sion Akt, P70S6K, eNOS phosphorylation level of ex-pression were significantly higher than those in NOR group, CON group, and DZ + LY group (P<0.01). There was no difference in expression level of ERK1/2 phosphorylation ( P >0.05 ) . Conclusion Diazoxide postconditioning through the activation of RISK signa-ling pathway can protect isolated rat hearts against is-chemia reperfusion injury.%目的：探讨特异性线粒体ATP敏感性钾通道开放剂二氮嗪(DZ)后处理能否激活再灌注损伤挽救激酶(RISK)信号通路减轻离体大鼠心脏缺血/再灌注损伤( IRI)。方法采用Langendorff装置建立大鼠离体心肌缺血/再灌注模型,将SD大鼠随机分为正常组( NOR)、对照组( CON)、二氮嗪后处理组( DZ)、LY拮抗二氮嗪组( DZ+ LY),每组8例。对比观察：①平衡末、再灌注末各组不同时点心功能的变化；于再灌注末取心肌组织并分离、提取蛋白,用Western blot分析蛋白激酶B (PKB/Akt),P70S6激酶(P70S6K),内皮型一氧化氮合酶(eNOS),细胞外调节激酶1/2(ERK1/2)磷酸化水平的表达。结果①心功能指标的变化：DZ组再灌注末心率(HR)、冠脉流量(CF)、左心室发展压(LVDP)、左心室舒张末压( LVEDP )、左心室内压上升最大速率(+ dp/dtmax )、左心室内压下降最大速率(-dp/dtmax )优于CON组、DZ+LY组(P<0.01),但差于NOR组(P<0.01)；平衡末心脏功能指标差异无统计学意义( P>0.05)。于再灌注末DZ组Akt、P70S6K、eNOS磷酸化水平的表达明显高于NOR组、CON组、DZ+LY组(P<0.01),各组ERK1/2磷酸化水平的表达差异无统计学意义( P>0.05)。结论二氮嗪后处理能够通过激活RISK信号通路减轻离体大鼠心脏IRI。