Altering CO2 during reperfusion of ischemic cardiomyocytes modifies mitochondrial oxidant injury
Altering CO2 during reperfusion of ischemic cardiomyocytes modifies mitochondrial oxidant injury
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DOI：
10.1097/01.ccm.0000269209.53450.ec
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发表时间：
2007-07-01
影响因子：
8.8
通讯作者：
Vanden Hoek, Terry L.
中科院分区：
文献类型：
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作者：
Lavani, Romeen;Chang, Wei-Tien;Vanden Hoek, Terry L.
目的：缺血心脏再灌注时组织CO2和pH的急性变化可能影响缺血/再灌注损伤。我们测试了心肌细胞缺血后二氧化碳的逐渐减少与急性减少是否会影响再灌注氧化剂和损伤。设计：比较实验室研究。设定：机构实验室。鸡胚心肌细胞。干预：在1小时的模拟缺血过程中，监测大约500个鸡心肌细胞的显微镜视野（Po-2为3-5 μ mol/L，Pco（2）为144 μ mol/L，pH 6.8），随后再灌注3小时（Po-2为149 μ mol/L，Pco（2）为36 μ mol/L，pH7.4），并与相对高碳酸血症（Pco（2）为71 μ mol/L，pH6.8）或低碳酸血症（Pco（2）为7 μ mol/L，测量和主要结果：测量的结果包括细胞活力（通过碘化丙啶）和氧化剂产生（通过2 '，7'-二氯荧光素氧化的活性氧物质和通过4，5-二氨基荧光素二乙酸酯氧化的一氧化氮[NO]）。与正常碳含量再灌注相比，高碳酸血症显著降低了细胞死亡，从54.8% +/- 4.0%降低到26.3% +/- 2.8%（p <0.001），显著降低了再灌注活性氧（p <0.05），并在再灌注后期增加了NO（p <0.01）。NO合成酶抑制剂N-硝基-L-精氨酸甲酯（200 μ M）逆转了这种氧化剂衰减（p <0.05）、NO增加（p <0.05）和由高碳酸再灌注引起的心脏保护（死亡增加至54.3% +/-6.0%[p <0.05]）。相反，低碳再灌注增加细胞死亡至80.4% +/-4.5%（p <0.01）。它还增加了活性氧近两倍（p = 0.052），而不影响此后的NO水平。当在再灌注时给予线粒体复合物III抑制剂stigmatellin（20 nM）时，增加的活性氧被减弱（p <0.05）。细胞死亡也从85.9% +/-4.5%降至52.2% +/-6.5%（p <0.01）。烟酰胺腺嘌呤二核苷酸磷酸氧化酶抑制剂夹竹桃素（300 μ M）没有再灌注活性氧species.Conclusions的影响：改变CO2含量在再灌注过程中可以显着影响心肌复苏后损伤，部分修改线粒体氧化剂和NO还原酶诱导的NO生产。
Objective: Acute changes in tissue CO2 and pH during reperfusion of the ischemic heart may affect ischemia/reperfusion injury. We tested whether gradual vs. acute decreases in CO2 after cardiomyocyte ischemia affect reperfusion oxidants and injury.Design: Comparative laboratory investigation. Setting: Institutional laboratory.Subjects: Embryonic chick cardiomyocytes.Interventions: Microscope fields of approximately 500 chick cardiomyocytes were monitored throughout 1 hr of simulated ischemia (Po-2 of 3-5 torr, Pco(2) of 144 torr, pH 6.8), followed by 3 hrs of reperfusion (Po-2 of 149 torr, Pco(2) of 36 torr, pH 7.4), and compared with cells reperfused with relative hypercarbia (Pco(2) Of 71 torr, pH 6.8) or hypocarbia (Pco(2) of 7 torr, pH 7.9).Measurements and Main Results: The measured outcomes included cell viability (via propidium iodide) and oxidant generation (reactive oxygen species via 2',7'-dichlorofluorescin oxidation and nitric oxide [NO] via 4,5-diaminofluorescein diacetate oxidation). Compared with normocarbic reperfusion, hypercarbia significantly reduced cell death from 54.8% +/- 4.0% to 26.3% +/- 2.8% (p < .001), significantly decreased reperfusion reactive oxygen species (p < .05), and increased NO at a later phase of reperfusion (p < .01). The NO synthase inhibitor N-nitro-L-arginine methyl ester (200 mu M) reversed this oxidant attenuation (p < .05), NO increase (p < .05), and the cardioprotection conferred by hypercarbic reperfusion (increasing death to 54.3% +/- 6.0% [p < .05]). Conversely, hypocarbic reperfusion increased cell death to 80.4% +/- 4.5% (p < .01). It also increased reactive oxygen species by almost two-fold (p = .052), without affecting the NO level thereafter. Increased reactive oxygen species was attenuated by the mitochondrial complex III inhibitor stigmatellin (20 nM) when given at reperfusion (p < .05). Cell death also decreased from 85.9% +/- 4.5% to 52.2% +/- 6.5% (p < .01). The nicotinamide adenine dinucleotide phosphate oxidase inhibitor apocynin (300 mu M) had no effect on reperfusion reactive oxygen species.Conclusions: Altering CO2 content during reperfusion can significantly affect myocardial postresuscitation injury, in part by modifying mitochondrial oxidants and NO synthase-induced NO production.