正己烷通过NLRP3炎症小体诱导神经毒性的分子机制

N-Hexane accumulates in human body due to chronic exposure and its metabolite 2,5-hexanedione (HD) can induce neurotoxicity characterized by distal axonal damage in central-peripheral nervous system. However, the mechanism remains unclear. We previously demonstrated that neuroinflammation mediates neurotoxicity induced by multiple environmental toxicants. By using 2,5-HD-intoxicated rats, our pilot study revealed that 2,5-HD induced activation of NLRP3 inflammasome and microglia. We therefore hypothesized that 2,5-HD may act on NLRP3 inflammasome to regulate neuroinflammation, eliciting central-peripheral neurotoxicity. By using 2,5-HD-generated rat model of n-hexane-induced neuropathy and primary cell cultures, we aimed to investigate how 2,5-HD regulates central-peripheral neuroinflammatory response through NLRP3 inflammasome using neurobehavioral, pathology and molecular biology methods, to elucidate the mechanisms of n-hexane-induced neuropathy. Furthermore, we aimed to determine the inhibitory effects of NLRP3 inflammasome antagonists against 2,5-HD-induced neurotoxicity, providing effective therapeutic strategy for preventing n-hexane intoxication.

正己烷长期接触可在人体内蓄积，其代谢产物2,5-己二酮(2,5-HD)可损伤中枢-外周远端轴突产生神经毒性作用，但其作用机制仍不清楚。我们既往研究发现神经炎症反应参与了多种环境毒物诱导的神经毒性。前期研究表明2,5-HD染毒大鼠后可激活NLRP3炎症小体，并促进小胶质细胞活化，推测2,5-HD可能通过NLRP3炎症小体调控神经炎症反应，从而诱发中枢-外周神经毒性。本课题拟利用2,5-HD染毒诱导的正己烷中毒性神经病大鼠模型和原代细胞培养，通过行为学、病理学和分子生物学等方法，研究2,5-HD中毒后通过NLRP3炎症小体调控中枢和外周神经炎症反应的分子机制，阐明正己烷中毒性神经病的分子机理；探讨2,5-HD中毒后阻断NLRP3炎症小体活化对神经损伤的抑制作用，为防治正己烷中毒提供有效策略。

中文摘要：.长期接触正己烷诱导以中枢-外周远端轴突损伤为主要特征的中毒性神经病。2,5-己二酮(2,5-HD)是正己烷体内代谢的终毒物，介导正己烷中毒性神经病发病，但作用机制不清。本课题利用2,5-HD染毒建立正己烷中毒性神经病大鼠和细胞模型，通过行为学、病理学和分子生物学等方法，研究2,5-HD通过NLRP3炎症小体调控中枢和外周神经系统损伤的分子机制。结果显示：1）随着染毒时间的增加，HD染毒大鼠逐渐出现步态不稳、后肢无力、拖地，最终无法站立直至瘫痪等典型的正己烷中毒性神经病特征；2）2,5-HD诱导大脑、脊髓和坐骨神经组织NLRP3炎症小体活化；3）NOX2激活和下游ROS及MAPK、NF-κB和PAK1通路活化在2,5-HD诱导NLRP3炎症小体活化中起重要作用；4）活化的NLRP3炎症小体可反作用于NOX2诱导其活化和ROS产生，形成一种自我驱动的恶性循环，从而促进炎症细胞M1极化，造成神经系统损伤；5）抑制NLRP3炎症小体活化和NOX2激活明显减轻2,5-HD诱导的神经毒性。因此，NLRP3炎症小体活化在2,5-HD神经毒性中起重要作用，阻断NLRP3炎症小体活化有明显的神经保护功能，为阐明正己烷中毒性神经病分子机制和筛选防治新靶点提供实验依据。