Roth Z'graggen Birgit, Urner Martin, Beck-Schimmer Beatrice, Schläpfer Martin
Institute of Physiology, University of Zurich, Zurich, Switzerland.
Interdepartmental Division of Critical Care Medicine and University of Toronto, Toronto, Canada.
BJA Open. 2022 Dec 30;5:100116. doi: 10.1016/j.bjao.2022.100116. eCollection 2023 Mar.
The volatile anaesthetic sevoflurane protects cardiac tissue from reoxygenation/reperfusion. Mitochondria play an essential role in conditioning. We aimed to investigate how sevoflurane and its primary metabolite hexafluoroisopropanol (HFIP) affect necrosis, apoptosis, and reactive oxygen species formation in cardiomyocytes upon hypoxia/reoxygenation injury. Moreover, we aimed to describe the similarities in the mode of action in a mitochondrial bioenergetics analysis.
Murine cardiomyocytes were exposed to hypoxia (0.2% O for 6 h), followed by reoxygenation (air with 5% CO for 2 h) in the presence or absence sevoflurane 2.2% or HFIP 4 mM. Lactate dehydrogenase (LDH) release (necrosis), caspase activation (apoptosis), reactive oxygen species, mitochondrial membrane potential, and mitochondrial function (Seahorse XF analyser) were measured.
Hypoxia/reoxygenation increased cell death by 44% (+31 to +55%, <0.001). Reoxygenation in the presence of sevoflurane 2.2% or HFIP 4 mM increased LDH release only by +18% (+6 to +30%) and 20% (+7 to +32%), respectively. Apoptosis and reactive oxygen species formation were attenuated by sevoflurane and HFIP. Mitochondrial bioenergetics analysis of the two substances was profoundly different. Sevoflurane did not influence oxygen consumption rate (OCR) or extracellular acidification rate (ECAR), whereas HFIP reduced OCR and increased ECAR, an effect similar to oligomycin, an adenosine triphosphate (ATP) synthase inhibitor. When blocking the metabolism of sevoflurane into HFIP, protective effects of sevoflurane - but not of HFIP - on LDH release and caspase were mitigated.
Together, our data suggest that sevoflurane metabolism into HFIP plays an essential role in cardiomyocyte postconditioning after hypoxia/reoxygenation injury.
挥发性麻醉剂七氟醚可保护心脏组织免受再氧合/再灌注损伤。线粒体在预处理过程中起着至关重要的作用。我们旨在研究七氟醚及其主要代谢产物六氟异丙醇（HFIP）在缺氧/再氧合损伤后如何影响心肌细胞中的坏死、凋亡和活性氧生成。此外，我们旨在通过线粒体生物能量分析描述两者作用模式的相似性。
将小鼠心肌细胞暴露于缺氧环境（0.2%氧气，持续6小时），随后在有或无2.2%七氟醚或4 mM HFIP存在的情况下进行再氧合（含5%二氧化碳的空气，持续2小时）。测量乳酸脱氢酶（LDH）释放（坏死）、半胱天冬酶激活（凋亡）、活性氧、线粒体膜电位和线粒体功能（Seahorse XF分析仪）。
缺氧/再氧合使细胞死亡增加44%（+31%至+55%，<0.001）。在存在2.2%七氟醚或4 mM HFIP的情况下进行再氧合，LDH释放仅分别增加了+18%（+6%至+30%）和20%（+7%至+32%）。七氟醚和HFIP可减轻凋亡和活性氧生成。两种物质的线粒体生物能量分析有很大差异。七氟醚不影响氧消耗率（OCR）或细胞外酸化率（ECAR），而HFIP降低OCR并增加ECAR，这种作用类似于三磷酸腺苷（ATP）合酶抑制剂寡霉素。当阻断七氟醚向HFIP的代谢时，七氟醚对LDH释放和半胱天冬酶的保护作用减弱，但HFIP的保护作用未减弱。
总之，我们的数据表明七氟醚代谢为HFIP在缺氧/再氧合损伤后的心肌细胞后处理中起重要作用。
