NADPH氧化酶介导的NLRP-1炎症小体激活在脑老化认知功能障碍中的作用及人参皂苷Rg1的调节作用

Why will some of the elderly population be brain aging-related cognitive dysfunction, and its mechanism is still unclear. NADPH oxidase mediated oxidative stress injury and NLRP1 inflammasome mediated inflammation are associated with many aging-related diseases. Our previous studies have shown that the NADPH expression and ROS production increased in pre-old rat brain. Our pre-experiment showed that NLRP1 and IL-1β expression was significantly increased in hippocampal neurons cultured for 10d. Ginsenosides Rg1 has anti-aging, anti-oxidation effect, our preliminary studies showed that Rg1 could reduce NADPH expression and ROS production in chronic stress mice neurons. Accordingly, we propose hypothesis that, in the course of brain aging, NADPH oxidase is upregulated, and the NLRP1 inflammasome is activated in neurons, which induce the cognitive dysfunction. Ginsenosides Rg1 can reduce neuronal NADPH oxidase, inhibit NLRP1 inflammasome activation, and improve the cognitive dysfunction. In the study: ① To study the dynamic changes and the relationship of brain aging cognitive impairment process and NADPH oxidase and NLRP1 inflammasome activation; ② To study the regulation and mechanisms of NADPH oxidase and NLRP1 inflammasome in brain aging cognitive dysfunction; ③ To study the effects and regulation of Ginsenosides Rg1 on NADPH oxidase and NLRP1 inflammasome activation in brain aging cognitive dysfunction. This study will provide new ideas for prevention and treatment of brain aging cognitive dysfunction.

为什么部分老年人群会出现脑老化认知功能障碍，其机制尚不清楚。NADPH氧化酶介导的氧化应激损伤和NLRP1炎症小体介导的炎症反应均与衰老相关疾病有关。我们前期研究显示，老前期大鼠脑内NADPH表达和ROS生成增加；我们预实验，海马神经元培养10d组NLRP1和IL-1β表达明显增加。人参皂苷 Rg1具有抗衰老、抗氧化等作用，我们前期研究显示，Rg1能减少慢性应激小鼠神经元ROS生成，下调NADPH表达。据此我们提出脑老化过程中神经元NADPH上调，激活NLRP1，导致认知功能障碍，Rg1下调神经元NADPH，抑制NLRP1激活，改善认知功能障碍的假说。本课题：①脑老化过程中神经元NADPH和NLRP1的动态变化及与认知功能障碍相关性；②NADPH对NLRP1调节在脑老化中的作用机制；③Rg1对NADPH和NLRP1的调节对认知功能障碍的影响。本课题研究将为防治脑老化认知功能障碍提供新思路。

脑老化是指随年龄增加，大脑组织结构、功能、形态等逐渐出现的衰退老化，导致学习和记忆等高级脑功能的障碍等。随着世界人口的老龄化，脑老化相关疾病发生率的上升，但其机制尚不完全清楚。氧化应激和炎症损伤是导致衰老和神经退行性疾病的重要因素。NADPH氧化酶是体内生成ROS的主要酶体，NLRP-1炎症小体是调节炎症反应的重要物质，NADPH氧化酶对NLRP-1炎症小体的调节作用是否参与了脑老化的发生和发展尚不清楚。人参皂苷 Rg1（Rg1）是人参的有效成分之一，具有促智、抗衰老、抗氧化和提高免疫力等作用。本课题主要研究NADPH氧化酶对NLRP-1炎症小体的调节在脑老化中的作用及Rg1的抗脑老化作用及机制。我们的实验结果显示：①体外原代培养海马神经元，与6d组比较，12d组海马神经元凋亡明显增加，MAP2表达减少，ROS、β-半乳糖苷酶（β-Gal）表达明显增加。同时，神经元NADPH氧化酶和NLRP1炎症小体相关蛋白的表达均明显增加，培养液中IL-1β和IL-18的释放量明显增加。②慢病毒转染NLRP1-siRNA干扰实验结果表明，与对照组比较，抑制Caspase1和下调NLRP1表达能明显减少海马神经元的凋亡和β-Gal的表达。③自然衰老动物实验结果显示，随着小鼠的衰老，尤其是20、24月龄小鼠活动和探索能力明显下降，Morris水迷宫检测学习和记忆能力均明显下降；同时衰老小鼠脑组织皮层和海马神经元ROS生成，β-半乳糖苷酶表达明显增加，皮层和海马区脑组织NADPH氧化酶和NLRP1炎症小体相关蛋白的表达均明显增加。④人参皂苷Rg1对SAMP8快速老化小鼠实验结果显示，SAMP8组小鼠在9月龄时出现了明显的衰老现象，活动能力和探索行为明显下降；皮层和海马CA1、CA3区ROS生成明显增加，NADPH氧化酶和NLPR1炎症小体明显激活，与SAMP8模型组比较，Rg1（10 mg/kg）可明显增加快速老化小鼠的学习和探索能力，减少ROS的生成，改善病理组织学损伤，明显减少NADPH氧化酶和NLPR1炎症小体相关蛋白的表达。我们的实验结果表明NADPH氧化酶介导的NLPR1炎症小体激活在脑老化认知功能损伤中起着重要的作用，Rg1可明显抑制NADPH氧化酶介导的NLPR1炎症小体激活，具有较好的抗脑老化作用。