右美托咪定对犬脓毒血症致急性肾损伤保护机制及药效靶位的确证

Acute renal injury caused by sepsis (SAKI) is a veterinary clinical high mortality rate (death rate) of infection complications. It is the focus of researches in this field to explore the effective prevention and treatment of drugs and to clarify the key mechanism of efficacy. In Previous studies, the inflammatory response is the focus of researches in SAKI on the pathophysiological mechanisms, in recent years, the relevant studies has shifted to oxidative stress injury. Our preliminary studies have found that DEX has a significant protective effect and can reduce oxidative stress injury in canine with SAKI. Therefore, our research group will establish the model of DEX intervening acute renal injury caused by sepsis. From the perspective of inhibiting oxidative stress factor generated, the purpose of this study is exploring the regulation mechanism of cholinergic anti-inflammatory pathway on NF-κB—iNOS—NO by the activation of DEX; Simultaneously, from the perspective of clearing the oxidative stress factor, we will research whether GSK-3β can be as a key site to regulate Nrf2/ARE through DEX activating PI3K/Akt. Based on the mentioned research foundation, we plan to explore the DEX efficacy target through the regulation of α2-AR and I2R, to further perfecting its molecular mechanism of pharmacological mechanism. This will pave a new way to provide the theoretical basis for the future clinical application of DEX in the treatment of canine SAKI and lay a foundation for revealing the protective mechanism.

脓毒血症致急性肾损伤（SAKI）是兽医临床高致死率的感染并发症。探寻有效防治药物及阐明关键药效机制的是该领域的研究焦点，以往对SAKI的病理生理学机制研究多集中在炎症反应方面，近年来研究的关注点开始向氧化应激损伤方面转移。课题组前期研究发现DEX对犬SAKI具有保护作用和减轻氧化应激损伤现象。因此课题组建立SAKI模型，应用DEX进行干预。从抑制氧化应激因子生成角度，探讨DEX通过胆碱能通路对NF-κB—iNOS—NO的调控机制；从加速清除氧化应激因子角度，探讨DEX激活PI3K/Akt后，以GSK-3β为关键位点调控Nrf2/ARE的作用机制。以此为基础，通过调控α2-AR及I2R，探寻DEX药效靶位，进一步完善其药理作用分子机制，为今后临床开展SAKI的治疗及进行相关的机制研究提供理论依据及试验基础。

脓毒血症致急性肾损伤（SAKI）是兽医临床高致死率的感染并发症。探寻有效防治药物及阐明关键药效机制的是该领域的研究焦点，以往对SAKI的病理生理学机制研究多集中在炎症反应方面，近年来研究的关注点开始向氧化应激损伤方面转移。本次研究表明：应用iNOS抑制剂后，显著抑制iNOS活力，RNS水平明显下调，氧化应激损伤得到明显改善。证明LPS能够通过激活NF-κB/AP-1介导的iNOS/NO信号通路，使机体RNS蓄积，造成氧化应激损伤，诱发SAKI；DEX可通过作用于α2-AR使NF-κB/AP-1通路中相关分子的mRNA及蛋白表达量下调，降低活性氮水平，改善氧化应激损伤，明显减轻SAKI；；另一方面DEX能够通过抗氧化应激作用降低SAKI损伤；DEX的作用机制是通过增加GSK-3β的磷酸化，调控Nrf2/ARE信号转导通路而发挥抗损伤作用；DEX可通过α2-AR和I2R对GSK-3β/Nrf2/ARE进行调控，而且DEX还可能存在其他途径对Nrf2/ARE起到激活调控的作用；LPS主要通过扰乱线粒体分裂与融合的动态平衡，破坏线粒体结构，进而引起线粒体功能障碍和肾小管上皮细胞凋亡，引发AKI。LPS也可引起细胞内Ca2+超载，从而激活CaMKII，促进Drp1介导的线粒体分裂，诱发AKI；si-Drp1抑制线粒体分裂后，可有效改善炎症反应、氧化应激、线粒体结构损伤和功能障碍、抑制线粒体途径的细胞凋亡，从而对LPS诱导的AKI起到保护作用；DEX通过α2-AR调节线粒体分裂/融合的动态平衡，改善线粒体功能和肾功能，对AKI起到保护作用；DEX可通过减少细胞内ROS的积累，抑制Ca2+/CaMKII信号的激活，从而抑制Drp1介导的线粒体分裂，恢复细胞内钙稳态，在脓毒症致AKI中发挥保护作用；DEX可通过激活SIRT1/PGC-1α通路，以SIRT1/PGC-1α依赖的方式抑制Drp1介导的线粒体分裂，促进Mfn2依赖的线粒体融合，改善线粒体结构和功能，从而发挥其抗氧化、抗凋亡作用，减轻脓毒症致AKI。按计划完成了课题任务，共发表中文核心文章3篇，SCI文章21篇，专利3个；培养博士2人，硕士14人。