Table_1_Benign Regulation of the Astrocytic Phospholipase A2-Arachidonic Acid Pathway: The Underlying Mechanism of the Beneficial Effects of Manual Acupuncture on CBF.DOC

BackgroundThe astrocytic phospholipase A2 (PLA2)-arachidonic acid (AA) pathway is crucial in understanding the reduction of cerebral blood flow (CBF) prior to cognitive deterioration. In complementary and alternative medicine, manual acupuncture (MA) is used as one of the most important therapies for Alzheimer’s disease (AD). The beneficial effects of MA on CBF were reported in our previous study. However, the underlying molecular mechanism remains largely elusive.
ObjectiveTo investigate the effect of MA on the astrocytic PLA2-AA pathway in SAMP8 mice hippocampi.
MethodsSAMP8 mice were divided into the SAMP8 control (Pc) group, the SAMP8 MA (Pm) group and the SAMP8 donepezil (Pd) group. SAMR1 mice were used as the SAMRl control (Rc) group. Mice in the Pd group were treated with donepezil hydrochloride at 0.65 μg/g. In the Pm group, MA was applied at Baihui (GV20) and Yintang (GV29) for 20 min. The above treatments were administered once a day for 26 consecutive days. The Morris water maze was applied to assess spatial learning and memory. Immunofluorescence staining, western blot and liquid chromatography-tandem mass spectrometry were used to investigate the expression of related proteins and measure the contents of the metabolic intermediates of the PLA2-AA pathway.
ResultsCompared with that in the Rc group, the escape latency in the Pc group significantly increased (p < 0.01); whereas, the platform crossover number and percentage of time and swimming distance in the platform quadrant decreased (p < 0.01). The hippocampal expression of PLA2, cyclooxygenase-1, cytochrome P450 proteins 2C23 and the levels of AA, prostaglandin E2 and epoxyeicosatrienoic acids of the Pc group was drastically higher than that in the Rc group (p < 0.01). These changes were reversed by MA and donepezil (p < 0.01 or p < 0.05).
ConclusionMA can effectively improve the learning and memory abilities of SAMP8 mice and has a negative regulatory effect on the PLA2-AA pathway. We propose that the increase of the arterial tone, which is induced by the inhibition of vasodilatory pathway, may be a reason for the beneficial effect of MA on CBF.

背景：星形胶质细胞磷脂酶A2（PLA2）-花生四烯酸（AA）通路是阐释认知衰退前脑血流量（CBF）降低机制的关键通路。在补充与替代医学领域，手工针刺（MA）是治疗阿尔茨海默病（AD）的重要疗法之一。本团队既往研究已证实手工针刺对脑血流量的改善作用，但其潜在分子机制仍基本未明。
目的：探讨手工针刺对SAMP8小鼠海马组织星形胶质细胞磷脂酶A2-花生四烯酸通路的影响。
方法：将SAMP8小鼠分为SAMP8对照组（Pc组）、SAMP8手工针刺组（Pm组）与SAMP8多奈哌齐组（Pd组），以SAMR1小鼠作为SAMR1对照组（Rc组）。Pd组小鼠给予盐酸多奈哌齐，给药剂量为0.65 μg/g体重。Pm组小鼠于百会（GV20）与印堂（GV29）穴进行手工针刺，留针20分钟。上述干预每日1次，连续干预26天。采用莫里斯水迷宫（Morris water maze）评估小鼠的空间学习与记忆能力；通过免疫荧光染色、蛋白质印迹（western blot）及液相色谱-串联质谱（liquid chromatography-tandem mass spectrometry）检测相关蛋白的表达水平，并定量测定磷脂酶A2-花生四烯酸通路代谢中间产物的含量。
结果：与Rc组相比，Pc组小鼠的逃避潜伏期显著延长（p < 0.01）；而平台穿越次数、平台象限停留时间占比及游泳距离均显著降低（p < 0.01）。Pc组小鼠海马组织中磷脂酶A2、环氧合酶-1（cyclooxygenase-1）、细胞色素P450 2C23（cytochrome P450 proteins 2C23）的表达水平，以及花生四烯酸、前列腺素E2（prostaglandin E2）、环氧二十碳三烯酸（epoxyeicosatrienoic acids）的含量均显著高于Rc组（p < 0.01）。手工针刺与多奈哌齐均可逆转上述异常变化（p < 0.01 或 p < 0.05）。
结论：手工针刺可有效改善SAMP8小鼠的学习记忆能力，并对星形胶质细胞磷脂酶A2-花生四烯酸通路产生负向调控作用。本研究推测，通过抑制血管舒张通路诱导动脉张力升高，可能是手工针刺改善脑血流量的有益作用的潜在机制。