CXCL12-CXCR4信号轴介导杏仁核胶质细胞-神经元对话参与局麻药惊厥后的负性情绪

Convulsion and the followed negative emotions are the most common adverse events of local anesthetic toxicity clinically, which severely affects the prognosis and even the living quality of patients. However, the underlying mechanisms remains unclear. Our previous studies detailedly evaluated the negative emotional behaviors on the experimental model of ropivacaine-induced convulsion, and found that the neuronal hyperactivity in the amygdala might be the key mechanism. Recently, our preliminary experiments showed that the negative emotions followed local anesthetics-induced convulsion was accompanied by noradrenaline accumulation, glial activation and CXCL12-CXCR4 signaling up-regulation in the amygdala. Based on previous studies, it is hypothesized that noradrenaline accumulated in the amygdala after local anesthetic toxicity and activated glial cells to release CXCL12, which modulated the activities of neuron through CXCR4 and eventually resulted in the occurrence of negative emotions. In the present study, we combined behavioral pharmacology, molecular biology and electrophysiological recordings to investigate the underlying cellular and molecular mechanisms at multiple levels. It is expected to provide experimental and theoretic basis for prevention and treatment of convulsion and negative emotions induced by local anesthetics.

惊厥及惊厥后的负性情绪是临床上最常见的局麻药毒性不良反应，严重影响患者的预后甚至生活质量。迄今为止，其发病机制依然不清。本课题组前期立足于实验性罗哌卡因惊厥模型，系统地评价了惊厥后负性情绪的行为学表现，首次发现杏仁核内神经元的活化是发病的关键因素。我们最新的研究结果表明：局麻药惊厥后负性情绪的发生伴随杏仁核内去甲肾上腺素释放增加、胶质细胞激活以及趋化因子CXCL12-CXCR4信号表达上调。结合前期相关研究，我们推测“局麻药惊厥后杏仁核内去甲肾上腺大量积累并激活胶质细胞释放趋化因子CXCL12，通过结合CXCR4受体影响神经元的功能活动状态，最终导致负性情绪的发生”。为论证该假说，本课题综合运用行为药理学，分子生物学，电生理等方法，从分子、细胞到整体动物水平进行研究，旨在为阐明局麻药惊厥后负性情绪的机制提供理论基础，为临床防治提供新思路新靶点。

局麻药是现代医药领域最常使用的药物之一。因过量使用或误入血管而造成的局麻药惊厥及惊厥后负性情绪的发生在临床屡见不鲜，严重影响患者的预后。目前为止，我们还不清楚局麻药惊厥后负性情绪发生的原因。因此，了解局麻药惊厥后负性情绪发生的病理生理进程及其细胞分子机制就变得十分迫切。本研究首先利用序贯法确定罗哌卡因的半数致惊厥剂量，并联合运用行为学、药理学、形态学、分子生物学及电生理记录等方法，开展了如下研究：（1） 杏仁核内CXCL12-CXCR4信号媒介的胶质细胞-神经元对话在局麻药惊厥后焦虑行为中的作用；（2）局麻药惊厥大鼠的痛觉敏化现象及其神经机制；（3）局麻药惊厥小鼠抑郁行为的神经机制及防治策略。研究结果发现：（1）局麻药惊厥后LC-BLA的去甲肾上腺素能神经投射激活，伴随BLA内NE和CXCL12释放增加以及小胶质细胞和星形胶质细胞活化，且CXCL12通过受体CXCR4导致BLA内神经元兴奋/抑制失衡，从而介导焦虑样行为的发生；（2）局麻药惊厥大鼠出现显著的双侧后足机械性痛敏，该痛敏至少持续5天，且局麻药惊厥显著加剧福尔马林引起的急性炎性痛并显著延长足底切口术后痛，而阻断下行性5-HT/5-HT3R信号可完全抑制上述现象；（3）局麻药惊厥小鼠出现显著的抑郁样行为，该抑郁样行为具有性别差异，雌性惊厥小鼠抑郁样行为持续到惊厥后7天，而雌性惊厥小鼠抑郁样行为至少持续至惊厥后14天，利用米诺环素抑制海马区异常活化的小胶质细胞以及促炎因子可显著缓解雌雄惊厥小鼠的抑郁样行为。综上，我们在本课题中系统的评价了局麻药惊厥后的神经精神后遗症（痛觉敏化、焦虑、抑郁），并进一步揭示了其神经化学机制，并据此提出了有效的防治策略。在本基金的资助下，课题组共发表7篇SCI文章和1篇中文核心文章。同时，课题组也获得了一些尚未发表的研究成果，推动课题后续进展。