二苯乙烯苷通过调控NMDA受体保护次声性脑损害的机制研究

The infrasound is an important environmental pollution factor which is extremely threatening to human health and easily overlooked. And the key factors of infrasound are concidered as the over-released or reabsorption disorder of Glutamate and hyperactivation of N-methyl-D-aspartate (NMDA) receptor which may induce brain damage such as cognitive dysfunction. In order to against infrasound, we screened a useful componant called 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG) from Polygonum multiflorum. Combined with the results of previous studies, we speculate that TSG can correct the calcium overload caused by over-released glutamate , antagonize NMDA receptors in downstream signaling pathways, then, promote the survival of neurons to against the brain damage caused by infrasound. According to the conjecture above, we arrange to investigate the effect of TSG on the survival rate of neurons in infrasound, to evaluate the effect of TSG on the cognitive ability on mice in infrasound, then, to investigate the effect of TSG on excitatory postsynaptic current mediated by NMDA receptor and the expression of NR2A and NR2B subunits, at last to screen the effect of TSG on these downstream proteins. These result of this project will clarity the neural molecular mechanism of TSG, and teach more for the research and development of infrasound-protect drug.

次声是极易被忽视的重要环境污染因素，能引发认知功能障碍等脑损伤。谷氨酸过度释放或重吸收障碍及过度激活N-甲基-D-天冬氨酸（NMDA）受体被认为是引起上述损伤的重要原因。为防护次声损伤，我们筛选到何首乌单体成分2,3,5,4'-四羟基二苯乙烯-2-O-β-D-葡萄糖苷（TSG）。结合前期研究结果我们推测，TSG能纠正谷氨酸过度释放导致的钙超载，拮抗NMDA受体下游死亡信号通路，促神经元存活，从而保护次声致认知功能障碍等脑损害。本项目拟在细胞、脑片和整体动物水平展开研究：观察TSG对神经元受次声辐射后存活率影响，评价TSG对次声暴露中小鼠认知能力影响；检测TSG对NMDA受体介导的兴奋性突触后电流，及突触内外NR2A和NR2B亚基表达影响；筛查TSG对下游信号蛋白影响。上述研究将完善TSG提高认知能力的神经分子机制研究，为次声性脑损伤防治药物研发奠基。

次声（频率低于20赫兹），广泛存在于自然界和人类日常生活中，通过生物共振的方式，作用于生物体的各器官和组织，产生广泛的生物学效应，对人类的健康造成极大威胁。在中高强度次声引起的损伤中，最为敏感和最为首要的是中枢神经系统的损害。课题组研究发现，何首乌（polygonum multiflorum thunb）的水溶性成分二苯乙烯苷（2,3,5,4'-四羟基二苯乙烯-2-O-β-D-葡萄糖苷，简称TSG）可改善次声暴露导致的小鼠神经退行性病变及认知能力损伤。课题组通过：①观察TSG对培养的神经元受次声辐射后存活率的影响，评价TSG对暴露于次声中小鼠的学习记忆能力的作用，明确了TSG对次声性脑损伤的保护作用；②检测TSG对突触NMDA受体的调节机制，包括TSG钙离子内流的作用，以及对突触小体中NR2A和NR2B亚型的NMDA受体水平的影响，结果证实，TSG可能通过调节突触内外NR2A和NR2B亚型NMDA受体的表达，减少胞内钙离子含量，减少钙离子内流，从而减少由次声造成的脑损伤；③筛选TSG对NMDA受体下游信号通路作用靶点的结果表明，TSG对p38 MAPK/ NF-κB死亡信号通路有调控作用，但p38 MAPK/ NF-κB通路并不是TSG唯一的作用靶点。上述实验结果表明，TSG通过调控NR2A、NR2B亚基表达，纠正次声引发的谷氨酸过度释放导致的钙超载，同时TSG通过抗氧化作用拮抗NMDA受体下游死亡信号通路，促进神经元存活，从而改善了次声导致的小鼠认知功能障碍等脑损害。本项目的完成，完善了TSG提高认知能力的神经分子机制研究，为TSG在防治次声性脑损伤的药物研发提供了理论基础。