Effect of diazoxide on flavoprotein oxidation and reactive oxygen species generation during ischemia-reperfusion:: a study on Langendorff-perfused rat hearts using optic fibers
Effect of diazoxide on flavoprotein oxidation and reactive oxygen species generation during ischemia-reperfusion:: a study on Langendorff-perfused rat hearts using optic fibers
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DOI：
10.1152/ajpheart.01345.2007
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发表时间：
2008-05-01
影响因子：
4.8
通讯作者：
Dos Santos, Pierre
中科院分区：
文献类型：
--
作者：
Pasdois, Philippe;Beauvoit, Bertrand;Dos Santos, Pierre
本研究分析了Langendorff灌注大鼠心脏缺血-再灌注方案期间的氧化剂产生，所述大鼠心脏用线粒体ATP敏感性钾通道（mitoKATP）开放剂（即，二氮嗪）。线粒体黄素蛋白的自发荧光和总NAD（P）H库的自发荧光以及对H2 O2或O-2（中心点-）敏感的染料的荧光[即，另一侧分别为二氢二氯荧光素（H2 DCF）和二氢乙啶（DHE）]，通过光纤在左心室壁表面进行无创测量。离体灌注大鼠心脏进行缺血-再灌注方案。用二氮嗪打开mitoK（ATP）（100 μ M）1）改善再灌注后心率-血压乘积的恢复（对照组为基线值的72 +/- 2 vs. 16.8 +/- 2.5%，P < 0.01），和2）在缺血和再灌注期间减少氧化剂的产生，（-46 +/-5%H2DCF氧化和-40 +/-3%DHE氧化对比对照组，P < 0.01）和再灌注（与对照组相比，-26 +/-2%H2DCF氧化和-23 +/-2%DHE氧化，P < 0.01）周期。所有这些影响被废除5-羟基癸酸（500 μ M），mitoKATP阻滞剂的共灌注。在预处理阶段，二氮嗪诱导一个短暂的，可逆的，5-羟基癸酸敏感的黄素蛋白和H2 DCF（但不是DHE）氧化。总之，二氮嗪介导的心脏保护是由一个温和的H2 O2生产过程中的预处理阶段和氧化剂的产生在随后的缺血和再灌注阶段的强烈减少。
This study analyzed the oxidant generation during ischemia-reperfusion protocols of Langendorff-perfused rat hearts, preconditioned with a mitochondrial ATP-sensitive potassium channel (mitoKATP) opener (i.e., diazoxide). The autofluorescence of mitochondrial flavoproteins, and that of the total NAD(P)H pool on the one hand and the fluorescence of dyes sensitive to H2O2 or O-2(center dot-) [i.e., the dihydrodichlorofluoroscein (H2DCF) and dihydroethidine (DHE), respectively] on the other, were noninvasively measured at the surface of the left ventricular wall by means of optic fibers. Isolated perfused rat hearts were subjected to an ischemia-reperfusion protocol. Opening mitoK(ATP) with diazoxide (100 mu M) 1) improved the recovery of the rate-pressure product after reperfusion (72 +/- 2 vs. 16.8 +/- 2.5% of baseline value in control group, P < 0.01), and 2) attenuated the oxidant generation during both ischemic (-46 +/- 5% H2DCF oxidation and -40 +/- 3% DHE oxidation vs. control group, P < 0.01) and reperfusion (- 26 +/- 2% H2DCF oxidation and - 23 +/- 2% DHE oxidation vs. control group, P < 0.01) periods. All of these effects were abolished by coperfusion of 5-hydroxydecanoic acid (500 mu M), a mitoKATP blocker. During the preconditioning phase, diazoxide induced a transient, reversible, and 5-hydroxydecanoic acid-sensitive flavoprotein and H2DCF (but not DHE) oxidation. In conclusion, the diazoxide-mediated cardioprotection is supported by a moderate H2O2 production during the preconditioning phase and a strong decrease in oxidant generation during the subsequent ischemic and reperfusion phases.