中国神经再生研究(英文版) ›› 2018, Vol. 13 ›› Issue (5): 819-826.doi: 10.4103/1673-5374.232529

• 原著:脑损伤修复保护与再生 • 上一篇    下一篇

右旋美托嘧啶减轻颅脑损伤的作用途径及机制

  

  • 收稿日期:2018-04-26 出版日期:2018-05-15 发布日期:2018-05-15
  • 基金资助:

    中国国家自然科学基金项目(81330029, 81671380),天津市自然科学基金项目(17JCZDJC35900

Dexmedetomidine attenuates traumatic brain injury: action pathway and mechanisms

Dong Wang1, 2, Xin Xu1, 2, Yin-Gang Wu1, 2, Li Lyu3, Zi-Wei Zhou1, 2, Jian-Ning Zhang1, 2   

  1. 1 Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China;
    2 Tianjin Neurological Institute, Key Laboratory of Post-Neuroinjury Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, China;
    3 Department of Cardiovascular, Tianjin Children’s Hospital, Tianjin, China
  • Received:2018-04-26 Online:2018-05-15 Published:2018-05-15
  • Contact: Jian-Ning Zhang or Zi-Wei Zhou,jianningzhang@hotmail.com or ziweizhou2009@hotmail.com.
  • Supported by:

    This work was supported by the National Natural Science Foundation of China, No. 81330029, 81671380; and the Natural Science Foundation of Tianjin City of China, No. 17JCZDJC35900

摘要:

颅脑损伤可引起强烈的炎症反应,加重继发性血脑屏障破坏、神经元损伤和神经功能障碍。右旋美托嘧啶是一种新型α2肾上腺素受体激动剂,能在多种中枢神经系统疾病中发挥保护作用。为此,实验设计拟通过对成年雄性C57BL/6J小鼠进行受控皮质撞击建立颅脑损伤模型,损伤后连续3d腹腔注射25μg/kg右旋美托嘧啶,观察概要对脑损伤的保护作用途径及机制。以mNSS评分评估神经功能,以滚轴实验评估精确运动协调能力和平衡能力,以免疫荧光检测损伤部位中Iba-1、髓过氧化物酶和ZO-1的免疫反应,以ELISA测量脑匀浆中白细胞介素1β,肿瘤坏死因子α和白细胞介素6的浓度,以干湿重法测量大脑含水量,以EB染色测量血脑屏障的破坏程度,以Western blot损伤大脑皮质周围NLRP3、caspase-1 p20、IL-1β、NF-κB p65、occludin以及ZO-1的表达水平,以流式细胞术损伤侧脑组织中细胞凋亡。结果显示右旋美托嘧啶治疗有效减轻了颅脑损伤模型小鼠的早期神经功能障碍和脑水肿,减轻了创伤后的过度炎症反应,上调了紧密连接蛋白表达,改善了继发性血脑屏障损伤,并减少神经元的凋亡。这些保护作用伴随着NF-κB信号通路抑制和NLRP3炎性小体表达的下调,表明右旋美托嘧啶对颅脑损伤急性期(3d)的炎症反应具有神经保护作用,并且这种作用是通过抑制NF-κB信号通路和NLRP3炎性小体激活途径所实现的。

orcid:0000-0002-7290-0994(Jian-Ning Zhang)
        0000-0002-5927-7835(Zi-Wei Zhou)

关键词: 颅脑损伤, 神经炎症反应, NF-&kappa, B, NLRP3炎性小体, 脑水肿, 血脑屏障, 紧密连接蛋白, 细胞凋亡, 神经保护, 右旋美托嘧啶

Abstract:

Traumatic brain injury induces potent inflammatory responses that can exacerbate secondary blood-brain barrier (BBB) disruption, neuronal injury, and neurological dysfunction. Dexmedetomidine is a novel α2-adrenergic receptor agonist that exert protective effects in various central nervous system diseases. The present study was designed to investigate the neuroprotective action of dexmedetomidine in a mouse traumatic brain injury model, and to explore the possible mechanisms. Adult male C57BL/6J mice were subjected to controlled cortical impact. After injury, animals received 3 days of consecutive dexmedetomidine therapy (25 μg/kg per day). The modified neurological severity score was used to assess neurological deficits. The rotarod test was used to evaluate accurate motor coordination and balance. Immunofluorescence was used to determine expression of ionized calcium binding adapter molecule-1, myeloperoxidase, and zonula occluden-1 at the injury site. An enzyme linked immunosorbent assay was used to measure the concentration of interleukin-1β (IL-1β), tumor necrosis factor α, and IL-6. The dry-wet weight method was used to measure brain water content. The Evans blue dye extravasation assay was used to measure BBB disruption. Western blot assay was used to measure protein expression of nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3), caspase-1 p20, IL-1β, nuclear factor kappa B (NF-κB) p65, occluding, and zonula occluden-1.Flow cytometry was used to measure cellular apoptosis. Results showed that dexmedetomidine treatment attenuated early neurological dysfunction and brain edema. Further, dexmedetomidine attenuated post-traumatic inflammation, up-regulated tight junction protein expression,and reduced secondary BBB damage and apoptosis. These protective effects were accompanied by down-regulation of the NF-κB and NLRP3 inflammasome pathways. These findings suggest that dexmedetomidine exhibits neuroprotective effects against acute (3 days)post-traumatic inflammatory responses, potentially via suppression of NF-κB and NLRP3 inflammasome activation.

Key words: nerve regeneration, traumatic brain injury, neuroinflammation, nuclear factor kappa B, NLRP3 inflammasome, brain edema, blood-brain barrier, tight junction proteins, apoptosis, neuroprotection, dexmedetomidine, neural regene