吡格列酮预处理对大鼠心脏缺血再灌注／缺氧再复氧线粒体结构及膜电势的影响

Effect of preconditioning with pioglitazone on ischemia reperfusion/hypoxia reoxygenation-induced mitochondrial structure and membrane potential in rats

目的:观察吡格列酮预处理对大鼠缺血再灌注心肌线粒体超微结构及缺氧再复氧心肌细胞线粒体膜电势的影响,并探讨可能机制。方法:建立大鼠缺血再灌注模型,分别设假手术对照(SO)组、单纯缺血再灌注(IR)组、吡格列酮预处理(Pio-P)组和5-HD+Pio组;缺血30min再灌注4h后取心室肌观察线粒体超微结构并行Flameng线粒体半定量分析。TUNEL法检测心肌细胞凋亡指数(AI);培养大鼠心肌细胞,分别分成对照组、缺氧再复氧(HR)组和不同浓度Pio-P组,缺氧1h再复氧2h后,利用JC-1染色流式细胞术检测线粒体膜电势(ΔΨm)变化。结果:IR组线粒体超微结构损害严重,Pio-P组明显减轻,5-HD+Pio组与IR组差异不大,IR组和Pio-P组线粒体Flameng评分为2.75±1.09和1.62±0.60,2组间差异显著(P(0.01)。IR组和Pio-P组AI为(55.44±6.63)%和(28.19±4.93)%,2组间差异显著(P(0.05),5-HD+Pio组与IR组差异无显著(P>0.05);HR组ΔΨm降低的细胞百分率为(56.52±2.87)%,较对照组(6.52±0.59)%差异显著(P(0.01);不同浓度(5μmol/L、10μmol/L及15μmol/L)Pio-P组ΔΨm降低的细胞百分率分别为(45.89±3.63)%、(17.13±1.37)%和(18.43±2.44)%,与HR组(56.52±2.87)%相比明显降低(P(0.05),但10μmol/L组及15μmol/L组差异无显著(P>0.05)。结论:吡格列酮预处理可以通过保护线粒体结构,抑制线粒体膜电势降低而起到抗缺血再灌注/缺氧再复氧损伤作用,该保护作用可被线粒体ATP敏感性钾通道阻滞剂所拮抗。

AIM： To observe the effect of preconditioning with pioglitazone on ischemia reperfusion/hypoxia reoxygenation - induced mitochondrial ultramicro - structure and membrane potential in rats. METHODS： Sprague - Dawley rats were randomly divided into four groups： sham- operated （SO） group, ischemia reperfusion （IR） group, pioglitazone preconditioning group （ Pio - P） and 5 - HD ＋ pioglitazone （5 - HD ＋ Pio） group. Apart from the SO group, IR, Pio - P and 5 - HD ＋ Pio groups were subjected to 30 min ischemia and 4 h reperfusion. The heart was quickly removed for observing the structure of mitochondria and measurement of the apoptosis index （AI） by TUNEL. Primary cultured cardiomyocytes of Sprague - Dawley rats were divided into control, hypoxic reoxygenation （HR） and different concentrations of Pio- P group. JC - 1 staining flowcytometry was adopted to examine mitochondrial membrane potential （△Aψm）. RESULTS： The injury of mitochondrial structure in IR group was severer than that in Pio - P group, while the difference between 5 - HD ＋ Pio group and IR group was not evident. Flameng score in Pio - P group（ 1.62 ±0. 60） was significantly lower than that in IR group （2. 75 ± 1.09）, P 〈0. 01. AI in Pio - P group （28. 19% ±4. 93% ） was lower than that in IR group （55.44% ±6. 63% ） ,P 〈0. 05. The rates of low △Aψm cells in （5 μmol/L,10 μmol/L and 15 μmol/L） Pio - P group were （45.89±3.63）%, （17.13 ±1.37）% and （18.43 ±2.44）%, significantly lower than that in HR group （56.52% ± 2. 87% ） ,P 〈0. 05, while the difference between 10 μmoL/L group and 15 μmol/L group was not significant （ P 〉 0. 05 ）. CONCLUSION： Pioglitazone protects the heart from ischemia reperfusion/hypoxia reoxygenation injury evidenced by improving mitochondrial ultrastructure and lessening the loss of mitochondrial membrane potential, and decreasing apoptosis. The cardioprotective effects can be inhibited by the blocker of mitochondrial ATP - sensitive potassium channels.