The protective effect of dexmedetomidine on LPS-induced acute lung injury through the HMGB1-mediated TLR4/NF-κB and PI3K/Akt/mTOR pathways
The protective effect of dexmedetomidine on LPS-induced acute lung injury through the HMGB1-mediated TLR4/NF-κB and PI3K/Akt/mTOR pathways
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DOI：
10.1016/j.molimm.2017.12.008
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发表时间：
2018-02-01
影响因子：
3.6
通讯作者：
Zhao, Guoqing
中科院分区：
文献类型：
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作者：
Meng, Lu;Li, Longyun;Zhao, Guoqing
本研究旨在评价右旋美托咪定(DEX)对内毒素(LPS)诱导的急性肺损伤(ALI)的保护作用，并探讨HMGB1介导的可能机制。体内观察肺组织病理变化，检测髓过氧化物酶(MPO)活性，评价地塞米松对肺的保护作用。检测大鼠肺泡灌洗液(BALF)、血清和肺组织中肿瘤坏死因子-α(TNF-α)、白介素6(IL-6)和白介素1β(IL-1β)的含量。测定血清超氧化物歧化酶(SOD)、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)等氧化指标。检测内毒素诱导的BEAS-2B细胞培养上清液中一氧化氮(NO)、肿瘤坏死因子-α(TNF-α)、白介素6(IL-6)和丙二醛(MDA)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)的含量。此外，我们还检测了高迁移率族蛋白-1蛋白(HMGB1)、Toll样受体4(TLR4)、髓系分化因子88(MyD88)、核因子-kappaB抑制物(I-kappa Bα)、p-I kappaBα、核因子kappaB、p-NF-kappaB、磷脂酰肌醇3‘-激酶(PI3K)、p-PI3K、蛋白激酶B(Akt)、p-Akt、哺乳动物雷帕霉素靶标(MTOR)和p-mTOR在脂多糖诱导的ALI大鼠和脂多糖诱导的BEAS-2B细胞中的表达。免疫组织化学和免疫荧光分析肺组织或BEAS-2B细胞中HMGB1的表达，以探讨DEX的作用机制。地塞米松能有效减轻肺组织病理改变，改善脂多糖刺激大鼠和BEAS-2B细胞MPO、SOD、MDA、GSH-Px、TNF-α、IL-6、IL-1β和NO水平。此外，地塞米松抑制HMGB1、TLR4、MyD88、p-NF-x13、p-PI3K、p-Akt和p-mTOR在体内和体外的表达。免疫组织化学和免疫荧光分析还显示，地塞米松抑制肺切片和BEAS-2B细胞中HMGB1的水平。HMGB1的抑制剂甘草酸处理证实HMGB1参与了DEX对内毒素诱导的所有HGMB1 siRNA的作用机制，在体外也证实了这一结果。综上所述，本研究表明地塞米松可能通过HMGB1介导的TLR4/NF-kappaB和PI3K/Akt/mTOR途径对内毒素诱导的ALI大鼠产生保护作用。
The aim of present study was to evaluate the protective effects of dexmedetomidine (DEX) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and investigate its possible mechanisms mediated by HMGB1. In vivo, pulmonary pathology observation and myeloperoxidase (MPO) activity were also examined to evaluate the protective effect of DEX in the lungs. Tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and interleukin-1 beta (IL-1 beta) in bronchoalveolar lavage fluid (BALF), serum and lung tissues LPS-induced rats were detected. The oxidative indices including superoxide dismutase (SOD), Malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) in serum were also determined. Additionally, nitric oxide (NO), TNF-alpha, IL-6 and MDA, SOD and GSH-Px in the supernatants of LPS-induced BEAS-2B cells were measured. Furthermore, we detected the protein expression of high mobility group box-1 protein (HMGB1), Toll-like receptor 4 (TLR4), myeloid differentiating factor 88 (MyD88), inhibitor of NF-kappa B (I kappa B alpha), p-I kappa B alpha, nuclear factor kappa-B (NF-kappa B), p-NF-kappa B, phosphatidylinositol 3'-kinase (PI3K), p-PI3K, protein kinase B (Akt), p-Akt, mammalian target of rapamycin (mTOR) and p-mTOR in LPS-induced ALI rats and LPS-induced BEAS-2B cells. Immunohistochemical and immunofluorescence analyses of HMGB1 in lung tissues or BEAS-2B cells were also conducted to evaluate the mechanisms of DEX. DEX effectively attenuated pulmonary pathology, and ameliorated the levels of MPO, SOD, MDA, GSH-Px, TNF-alpha, IL-6, IL-1 beta and NO in LPS-stimulated rats and BEAS-2B cells. Additionally, treatment with DEX inhibited the expression of HMGB1, TLR4, MyD88, p-NF-x13, p-PI3K, p-Akt and p-mTOR in vivo and in vitro. Immunohistochemical and immunofluorescence analyses also showed that DEX suppressed HMGB1 levels in lung sections and BEAS-2B cells. Treatment with glycyrrhizin, an inhibitor of HMGB1, confirmed that HMGB1 was involved in the mechanism of DEX on LPS-induced ALL The transfection of HGMB1 siRNA also confirmed these findings in vitro. In conclusion, the present study showed that DEX exerted a protective effect on LPS-induced ALI rats likely through the HMGB1-mediated TLR4/NF-kappa B and PI3K/Akt/mTOR pathways.