The results of a previous study demonstrated that heat stress (HS) triggered oxidative stress, which in turn induced the apoptosis of epithelial cells. These results uncovered a novel mechanism underlying the activation of NF‑κB in primary human umbilical vein endothelial cells. The present study aimed to further investigate the role of NF‑κB/IκBα signaling pathways in the inhibition of HS‑induced reactive oxygen species (ROS) generation and cytotoxicity in endothelial cells. The results of the present study demonstrated that HS triggered a significant amount of NF‑κB and IκBα nuclear translocation without IκBα degradation in a time‑dependent manner. Mutant constructs of IκBα phosphorylation sites (Ser32, Ser36) were employed in rat pulmonary microvascular endothelial cells (PMVECs). Cell Counting Kit‑8 assays demonstrated that both the small interfering (si)RNA‑mediated knockdown of p65 and IκBα mutant constructs significantly decreased cell viability and aggravated ROS accumulation in HS‑induced rat PMVECs compared with the control. Additionally, western blot analysis revealed that p65 siRNA attenuated the protein expression of IκBα. However, IκBα mutant constructs failed to attenuate NF‑κB activation and nuclear translocation, indicating that IκBα‑independent pathways contributed to NF‑κB activity and nucleus translocation in a time‑dependent manner following HS. Collectively, the results of the present study suggested that the NF‑κB/IκBα pathway was essential for resistance to HS‑induced ROS production and cytotoxicity in rat PMVECs, and that it could be a potential therapeutic target to reduce the mortality and morbidity of heat stroke.

中文翻译：

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NF-κB/IκBα 信号通路对于抵抗热应激诱导的肺微血管内皮细胞产生 ROS 至关重要。

先前一项研究的结果表明，热应激 (HS) 引发氧化应激，进而诱导上皮细胞凋亡。这些结果揭示了原代人脐静脉内皮细胞中 NF-κB 激活的新机制。本研究旨在进一步研究 NF-κB/IκBα 信号通路在抑制 HS 诱导的内皮细胞活性氧 (ROS) 生成和细胞毒性中的作用。本研究的结果表明，HS 以时间依赖性方式触发了大量的 NF-κB 和 IκBα 核转位，而 IκBα 没有降解。在大鼠肺微血管内皮细胞 (PMVECs) 中使用了 IκBα 磷酸化位点 (Ser32、Ser36) 的突变构建体。细胞计数 Kit-8 分析表明，与对照相比，小干扰 (si)RNA 介导的 p65 和 IκBα 突变构建体敲低均显着降低了 HS 诱导的大鼠 PMVEC 中的细胞活力并加重了 ROS 积累。此外，蛋白质印迹分析显示 p65 siRNA 减弱了 IκBα 的蛋白质表达。然而，IκBα 突变构建体未能减弱 NF-κB 活化和核转位，表明 IκBα 非依赖性途径在 HS 后以时间依赖性方式促进 NF-κB 活性和核转位。总的来说，本研究的结果表明，NF-κB/IκBα通路对于大鼠 PMVECs 对 HS 诱导的 ROS 产生和细胞毒性的抵抗是必不可少的，