Department of Anesthesiology, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China.
Department of Anesthesiology, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China.
Biomed Pharmacother. 2022 Oct;154:113572. doi: 10.1016/j.biopha.2022.113572. Epub 2022 Aug 18.
The present study aimed to investigate whether dexmedetomidine (Dex) exerts cardioprotection effect through inhibiting ferroptosis. Myocardial ischemia/reperfusion injury (MIRI) was induced in Sprague-Dawley rats in Langendorff preparation. The hemodynamic parameters were recorded. Triphenyltetrazolium chloride (TTC) staining was used to determine infarct size. In the in vitro study, the model of hypoxia/reoxygenation (HR) was established in H9c2 cells. Cell viability and apoptosis were detected using cell counting kit 8 (CCK-8), and AV/PI dual staining respectively. Lipid peroxidation as measured by the fluorescence of the fatty acid analog C11-BODIPY581/591 probe and intracellular ferrous iron levels were measured by fluorescence of Phen Green SK (PGSK) probe, whereas immunofluorescence and transmission electron microscopy were also used to examine ferroptosis. Protein levels were investigated by Western blot. The interactions of AMPK/GSK-3β signaling with Nrf2 were also assessed through AMPK inhibition and GSK-3β overexpression. Our findings indicated that Dex significantly alleviated myocardial infarction, improved heart function, and decreased HR-induced accumulation of Fe and lipid peroxidation in cardiomyocytes. Dex significantly increased the expression levels of Nrf2, SLC7A11, and GPX4. However, inhibition of Nrf2 by ML385 blunted the protective effect of Dex in HR-treated H9c2 cells. Inhibition of AMPK with a specific inhibitor or siRNA decreased the expression levels of phosphorylation of GSK-3β and Nrf2 induced by Dex. Overexpression of GSK-3β resulted in lower levels of nuclear Nrf2, whereas depression of GSK-3β enhanced expressions of nuclear Nrf2. In conclusion, Dex protects hearts against MIRI-induced ferroptosis via activation of Nrf2 through AMPK/GSK-3β signaling pathway.
本研究旨在探讨右美托咪定（Dex）是否通过抑制铁死亡发挥心脏保护作用。在 Langendorff 制备中诱导 Sprague-Dawley 大鼠心肌缺血/再灌注损伤（MIRI）。记录血流动力学参数。三苯基四氮唑（TTC）染色用于确定梗死面积。在体外研究中，在 H9c2 细胞中建立缺氧/复氧（HR）模型。使用细胞计数试剂盒 8（CCK-8）分别检测细胞活力和细胞凋亡，AV/PI 双重染色。通过脂肪酸类似物 C11-BODIPY581/591 探针的荧光检测脂质过氧化，通过 Phen Green SK（PGSK）探针的荧光检测细胞内亚铁离子水平，免疫荧光和透射电子显微镜也用于检测铁死亡。通过 Western blot 检测蛋白水平。还通过 AMPK 抑制和 GSK-3β 过表达评估 AMPK/GSK-3β 信号与 Nrf2 的相互作用。我们的研究结果表明，Dex 显著减轻心肌梗死，改善心功能，并减少 HR 诱导的心肌细胞中铁和脂质过氧化的积累。Dex 显著增加了 Nrf2、SLC7A11 和 GPX4 的表达水平。然而，用 ML385 抑制 Nrf2 减弱了 Dex 在 HR 处理的 H9c2 细胞中的保护作用。用特异性抑制剂或 siRNA 抑制 AMPK 降低了 Dex 诱导的 GSK-3β 和 Nrf2 磷酸化的表达水平。GSK-3β 的过表达导致核 Nrf2 的水平降低，而 GSK-3β 的抑制增强了核 Nrf2 的表达。总之，Dex 通过激活 AMPK/GSK-3β 信号通路通过 Nrf2 保护心脏免受 MIRI 诱导的铁死亡。
