右美托咪定通过 αAR/PI3K/Akt 通路减轻肾缺血再灌注损伤诱导的肺细胞凋亡。
Dexmedetomidine attenuates lung apoptosis induced by renal ischemia-reperfusion injury through αAR/PI3K/Akt pathway.
机构信息
Department of Anesthesiology, Southwest Hospital, Third Military Medical University, 30 Gaotanyan Road, Chongqing, 400038, China.
Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea & Westminster Campus, London, UK.
出版信息
J Transl Med. 2018 Mar 23;16(1):78. doi: 10.1186/s12967-018-1455-1.
BACKGROUND
Acute lung injury caused by renal ischemia-reperfusion is one of the leading causes of acute kidney injury-related death. Dexmedetomidine, an α-adrenergic agonist sedative, has been found to have protective effects against acute kidney injury and remote lung injury. We sought to determine whether dexmedetomidine can exert its anti-apoptotic effects in acute lung injury after acute kidney injury, in addition to its common anti-inflammatory effects, and to determine the underlying mechanisms.
METHODS
In vivo, acute kidney injury was induced by 60 min of kidney ischemia (bilateral occlusion of renal pedicles) followed by 24 h of reperfusion. Mice received dexmedetomidine (25 µg/kg, i.p.) in the absence or presence of α-adrenergic antagonist atipamezole (250 µg/kg, i.p.) before IR. Histological assessment of the lung was conducted by HE staining and arterial blood gases were measured. Lung apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay. The expression of caspase 3 and p-Akt in lung tissue was detected by western blot. In vitro, C57BL/6J mice pulmonary microvascular endothelial cells were treated with serum from mice obtained following sham or IR. Dexmedetomidine was given before serum stimulation in cells, alone or with atipamezole or LY294002. Cell viability was assessed by CCK 8 assay. Cell apoptosis was examined by Hoechst staining and Annexin V-FITC/PI staining flow cytometry analysis. Mitochondrial membrane potential was measured by flow cytometry. The expression of p-Akt, caspase 3, Bcl-2 and Bax was measured by western blot.
RESULTS
In vivo, dexmedetomidine remarkably mitigated pathohistological changes and apoptosis and significantly increased p-Akt expression in the lung. In addition, dexmedetomidine also slightly improved oxygenation in mice after IR, which can be abolished by atipamezole. In vitro, dexmedetomidine significantly inhibited IR serum-induced loss of viability and apoptosis in PMVECs. Dexmedetomidine increased p-Akt in a time- and dose-dependent manner, and down-regulated the expression of caspase 3 and Bax and up-regulated the Bcl-2 expression in PMVECs. The changes of MMP were also improved by dexmedetomidine. Whilst these effects were abolished by Atipamezole or LY294002.
CONCLUSION
Our results demonstrated that dexmedetomidine attenuates lung apoptosis induced by IR, at least in part, via αAR/PI3K/Akt pathway.
背景
肾缺血再灌注引起的急性肺损伤是急性肾损伤相关死亡的主要原因之一。α-肾上腺素能激动剂镇静剂右美托咪定已被发现对急性肾损伤和远隔肺损伤具有保护作用。我们试图确定右美托咪定除了其常见的抗炎作用外，是否还能在急性肾损伤后急性肺损伤中发挥抗细胞凋亡作用，并确定其潜在机制。
方法
在体内，通过 60 分钟的肾缺血（双侧肾蒂夹闭）诱导急性肾损伤，然后再灌注 24 小时。在 IR 前，小鼠接受右美托咪定（25μg/kg，腹腔注射），并在存在或不存在α-肾上腺素能拮抗剂阿替美唑（250μg/kg，腹腔注射）的情况下接受右美托咪定。通过 HE 染色评估肺的组织学变化，并测量动脉血气。通过末端脱氧核苷酸转移酶介导的 dUTP 缺口末端标记法评估肺细胞凋亡。通过 Western blot 检测肺组织中 caspase 3 和 p-Akt 的表达。在体外，用 sham 或 IR 后小鼠的血清处理 C57BL/6J 小鼠肺微血管内皮细胞。在细胞中用右美托咪定预先处理血清刺激，单独或与阿替美唑或 LY294002 一起。通过 CCK 8 测定评估细胞活力。通过 Hoechst 染色和 Annexin V-FITC/PI 染色流式细胞术分析检测细胞凋亡。通过流式细胞术测量线粒体膜电位。通过 Western blot 测量 p-Akt、caspase 3、Bcl-2 和 Bax 的表达。
结果
在体内，右美托咪定显著减轻了肺的病理变化和凋亡，并显著增加了肺中的 p-Akt 表达。此外，右美托咪定还略微改善了 IR 后小鼠的氧合作用，这种作用可以被阿替美唑所消除。在体外，右美托咪定显著抑制了 PMVECs 中由 IR 血清引起的活力丧失和凋亡。右美托咪定呈时间和剂量依赖性增加 p-Akt，并下调 caspase 3 和 Bax 的表达，上调 PMVECs 中的 Bcl-2 表达。MMP 的变化也得到了右美托咪定的改善。而这些作用被阿替美唑或 LY294002 所消除。
结论
我们的结果表明，右美托咪定通过αAR/PI3K/Akt 通路至少部分减轻了 IR 诱导的肺细胞凋亡。
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