College of Medicine, Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois, USA.
College of Medicine, Department of Anesthesiology, University of Arizona, Tucson, Arizona, USA.
Oxid Med Cell Longev. 2020 Feb 12;2020:2563764. doi: 10.1155/2020/2563764. eCollection 2020.
Norepinephrine (NE) is the naturally occurring adrenergic agonist that is released in response to hypotension, and it is routinely administered in clinical settings to treat moderate to severe hypotension that may occur during general anesthesia and shock states. Although NE has incontestable beneficial effects on blood pressure maintenance during hypotensive conditions, deleterious effects of NE on endothelial cell function may occur. In particular, the role of reactive oxygen species (ROS) and NADPH oxidase (Nox) on the deleterious effects of NE on endothelial cell function have not been fully elucidated. Therefore, we investigated the effects of NE on ROS production in rat lung microvascular endothelial cells (RLMEC) and its contribution to cell death. RLMEC were treated with NE (5 ng/mL) for 24 hours and ROS production was assessed by CellROX and DCFDA fluorescence. Nox activity was assessed by NADPH-stimulated ROS production in isolated membranes and phosphorylation of p47phox; cell death was assessed by flow cytometry and DNA fragmentation. Caspase activation was assessed by fluorescent microscopy. Nox1, Nox2, and Nox4 mRNA expression was assessed by real-time PCR. NE increased ROS production, Nox activity, p47phox phosphorylation, Nox2 and Nox4 mRNA content, caspase-3 activation, and RLMEC death. Phentolamine, an -adrenoreceptor antagonist, inhibited NE-induced ROS production and Nox activity and partly inhibited cell death while -blockade had no effect. Apocynin and PEGSOD inhibited NE-induced caspase-3 activation and cell death while direct inhibition of caspase-3 abrogated NE-induced cell death. PEG-CAT inhibited NE-induced cell death but not caspase-3 activation. Collectively, these results indicate that NE induces RLMEC death via activation of Nox by -adrenergic signaling and caspase-3-dependent pathways. NE has deleterious effects on RLMECs that may be important to its long-term therapeutic use.
去甲肾上腺素（NE）是一种天然存在的拟交感神经胺，在低血压时释放，并在临床环境中常规用于治疗可能发生在全身麻醉和休克状态下的中度至重度低血压。尽管 NE 在低血压情况下维持血压方面具有不可争议的有益作用，但 NE 对内皮细胞功能的有害影响可能会发生。特别是，活性氧物种（ROS）和 NADPH 氧化酶（Nox）在 NE 对内皮细胞功能的有害影响中的作用尚未完全阐明。因此，我们研究了 NE 对大鼠肺微血管内皮细胞（RLMEC）中 ROS 产生的影响及其对细胞死亡的贡献。RLMEC 用 NE（5ng/mL）处理 24 小时，并用 CellROX 和 DCFDA 荧光评估 ROS 产生。通过分离膜中的 NADPH 刺激的 ROS 产生和 p47phox 的磷酸化来评估 Nox 活性；通过流式细胞术和 DNA 片段化评估细胞死亡；通过荧光显微镜评估半胱天冬酶激活。通过实时 PCR 评估 Nox1、Nox2 和 Nox4 mRNA 表达。NE 增加了 ROS 产生、Nox 活性、p47phox 磷酸化、Nox2 和 Nox4 mRNA 含量、caspase-3 激活和 RLMEC 死亡。-肾上腺素受体拮抗剂酚妥拉明抑制了 NE 诱导的 ROS 产生和 Nox 活性，并部分抑制了细胞死亡，而 -阻断无影响。阿朴肉桂酸和 PEGSOD 抑制了 NE 诱导的 caspase-3 激活和细胞死亡，而直接抑制 caspase-3 则消除了 NE 诱导的细胞死亡。PEG-CAT 抑制了 NE 诱导的细胞死亡，但不抑制 caspase-3 激活。总之，这些结果表明，NE 通过 -肾上腺素能信号和 caspase-3 依赖性途径激活 Nox 诱导 RLMEC 死亡。NE 对 RLMEC 具有有害影响，这可能对其长期治疗用途很重要。
