Department of Respiratory and Critical Care Medicine, Zhangzhou Affiliated Hospital of Fujian Medical University, Zhangzhou, Fujian Province, China.
Department of Emergency Medicine, Zhangzhou Affiliated Hospital of Fujian Medical University, Zhangzhou, Fujian Province, China.
Sleep Breath. 2023 Oct;27(5):2069-2076. doi: 10.1007/s11325-023-02801-8. Epub 2023 Mar 1.
Ferroptosis is reported to be involved in the chronic intermittent hypoxia (CIH)-related liver damage in vivo. Nuclear factor E2-related factor 2 (Nrf2) has an essential role in the regulation of ferroptosis. This study tested the hypothesis that intermittent hypoxia (IH) could lead to hepatocyte ferroptosis in vitro and the function of Nrf2 in IH-induced hepatocyte ferroptosis.
BRL-3A cells (rat liver cells) were exposed to normoxia or IH. The protocol of IH consisted of 32 cycles of 60-min hypoxic exposure with 30-min reoxygenation phase (nadir of 1% oxygen to peak of 20% oxygen). Ferroptosis was evaluated by cell viability, iron concentration, lipid reactive oxygen species (ROS), protein content of ferritin heavy chain (FTH1), and glutathione peroxidase 4 (GPX4). Both ferrostatin-1 (a ferroptosis inhibitor) and Nrf2 interfering RNA were applied to treat BRL-3A cells, respectively.
IH exposure induced ferroptosis in BRL-3A cells with decreased cell viability and increased total iron content and lipid ROS levels. The protein contents of GPX4 and FTH1 in IH group were markedly lower than that in normoxic control. Ferroptosis inhibitor ferrostatin-1 alleviated IH-induced ferroptosis in BRL-3A cells. IH treatment enhanced expression of Nrf2, and Nrf2 knockdown augmented IH-induced ferroptosis in BRL-3A cells.
The results revealed that Nrf2 played a protective role during IH-induced ferroptosis in BRL-3A cells. The finding provides a therapeutic target for obstructive sleep apnea-related liver injury.
据报道，铁死亡参与了体内慢性间歇性低氧（CIH）相关的肝损伤。核因子 E2 相关因子 2（Nrf2）在铁死亡的调控中起着至关重要的作用。本研究检验了间歇性低氧（IH）是否会导致体外肝细胞铁死亡以及 Nrf2 在 IH 诱导的肝细胞铁死亡中的作用这一假说。
将 BRL-3A 细胞（大鼠肝细胞）暴露于常氧或 IH 中。IH 的方案由 32 个 60 分钟低氧暴露周期和 30 分钟复氧阶段（氧分压从 1%降至 20%的低谷）组成。通过细胞活力、铁浓度、脂质活性氧（ROS）、铁蛋白重链（FTH1）和谷胱甘肽过氧化物酶 4（GPX4）的蛋白含量来评估铁死亡。分别用铁死亡抑制剂 ferrostatin-1 和 Nrf2 干扰 RNA 处理 BRL-3A 细胞。
IH 暴露诱导了 BRL-3A 细胞的铁死亡，细胞活力降低，总铁含量和脂质 ROS 水平升高。与常氧对照组相比，IH 组的 GPX4 和 FTH1 蛋白含量明显降低。铁死亡抑制剂 ferrostatin-1 缓解了 IH 诱导的 BRL-3A 细胞铁死亡。IH 处理增强了 Nrf2 的表达，而 Nrf2 敲低则增强了 IH 诱导的 BRL-3A 细胞铁死亡。
结果表明，Nrf2 在 IH 诱导的 BRL-3A 细胞铁死亡中发挥了保护作用。这一发现为阻塞性睡眠呼吸暂停相关肝损伤提供了治疗靶点。
