右美托咪定激活Nrf2-ARE信号通路对创伤性脑损伤的抗氧化作用 |
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作者姓名: | 张晓秀 吴海鹰 王艳雪 钱传云 |
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作者单位: | 1. 650032 昆明医科大学第一附属医院急救医学部 |
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基金项目: | 云南省医疗卫生内设研究机构项目(2017NS065); 昆明医科大学研究生创新基金(2017S088); 云南省科技厅-昆明医科大学应用基础研究联合项目(2014FA012) |
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摘 要: | 目的探讨右美托咪定(DEX)对创伤性脑损伤(TBI)模型大鼠的神经保护作用、氧自由基清除及脑组织红系衍生的核因子相关因子2(Nrf2)-抗氧化反应原件(ARE)信号通路参与的机制。
方法选择健康成年雄性大鼠体重300~350 g构建TBI模型,将60只SD大鼠分为3组:假手术组(Sham组)、TBI组和TBI+DEX组,每组20只。其中Sham组仅去除脑颅骨不打砸,TBI组和DEX组均采用改良自由落体装置制备TBI模型,随后在造模后1 h分别给予等量0.9%NaCl和DEX(100 μg/kg)处理。通过采用改良神经功能缺损评分(mNSS)评价神经功能,脑组织干湿重称量法评价脑水肿。使用酶活试剂盒检测损伤24 h后抗氧化酶超氧化物歧化酶(SOD)和丙二醛(MDA)。最后使用免疫印迹试验(Western blot)和实时定量基因扩增荧光检测系统(RT-qPCR)的方法检测Nrf2-ARE信号通路及其下游分子血红素加氧酶1(HO-1)、醌氧化还原酶1(NQO-1)的表达水平,表达情况。
结果与TBI组相比,DEX组mNSS评分显著降低(P<0.05),DEX组能够明显减少脑水肿(P<0.05);DEX组能够明显增加抗氧化酶SOD活性,降低氧化应激产物MDA的水平(P<0.05)。
结论DEX能够激活Nrf2-ARE信号通路诱导下游抗氧化/解毒酶等靶基因的表达,从而抑制氧化应激损伤发挥神经保护作用。
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关 键 词: | 右美托咪定 Nrf2-ARE信号通路 创伤性脑损伤 氧化应激 |
收稿时间: | 2018-03-15 |
Antioxidant effects of dexmedetomidine in traumatic brain injury rats by activating Nrf2-ARE pathway |
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Authors: | Xiaoxiu Zhang Haiying Wu Yanxue Wang Chuanyun Qian |
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Affiliation: | 1. Department of Emergency and Intensive Care Unit, First Affiliated Hospital of Kunming Medical University, Kunming 650032, China |
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Abstract: | ObjectiveTo investigate the neuroprotective effect of dexmedetomidine in traumatic brain injury (TBI) rat model and the relationship with clearance of oxygen free radicals and the erythroid-derived nuclear factor-related factor 2 (Nrf2)-antioxidant/electrophilic response element (ARE) signal pathway.
MethodsHealthy adult male SD rats weighing 300-350 g were selected to construct a TBI model. Sixty rats were divided into three groups: sham operation group (Sham group), traumatic brain injury group (TBI group) and dexmedetomidine (TBI+ DEX group) group. In Sham group, only brain skulls were removed. In TBI and TBI+ DEX groups, the rats were all prepared with a modified free-fall device to induce traumatic brain injury . Rats in TBI and TBI+ DEX groups received same amount of saline and dexmedetomidine (100 μg/kg) treatment 1 h after the onset of TBI respectively. Neurological function was evaluated by modified neurological deficit scores (mNss), and cerebral edema was evaluated by brain dry-wet weight method. The enzyme activity kit was used to detect the antioxidant enzymes SOD and MDA after 24 hours of injury. Finally, Western blot, RT-qPCR and immunofluorescence methods were used to detect the expression level of Nrf2-ARE signaling pathway and its downstream molecules HO-1, NQO-1expression.
ResultsCompared with TBI group, mNss scores in DEX group were significantly lower (P<0.05). DEX could significantly reduce brain edema (P<0.05); DEX could significantly reduce the levels of antioxidant enzyme SOD and oxidative stress product MDA (P<0.05).
ConclusionDEX can activate Nrf2-ARE signaling pathway to induce the expression of target genes such as antioxidant/detoxifying enzymes downstream to inhibit oxidative stress and exert neuroprotection. |
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Keywords: | Dexmedetomidine Nrf2-ARE signal pathway Traumatic brain injury Oxidative stress |
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