Acupuncture improves dendritic structure and spatial learning and memory ability of Alzheimer's disease mice

Acupuncture can improve the cognitive state of Alzheimer's disease, but its mechanism is not clear. Dendritic atrophy and synaptic loss in Alzheimer's disease brain are positively correlated with cognitive damage. Therefore, we speculated that the effect of acupuncture on improving cognitive function may be associated with reduced dendritic damage in the brain. Acupuncture at Qihai (CV6), Zhongwan (CV12), Danzhong (CV17), bilateral Zusanli (ST36), and bilateral Xuehai (SP10) acupoints was performed once a day (1-day rest after 6-day treatment) for 14 consecutive days. Senescence-accelerated mouse prone 8 (SAMP8) mice without acupuncture and senescence-accelerated mouse resistant 1 (SAMR1) mice were used as normal controls. After 14 days of treatment, spatial learning and memory ability of mice was assessed in each group using the Morris water maze. Dendritic changes of pyramidal cells in the hippocampal CA1 region were analyzed by quantitative Golgi staining. Our results showed that acupuncture shortened escape latency and lengthened retention time of the former platform quadrant in SAMP8 mice. Further, SAMP8 mice exhibited a significant increase in the number of apical and basal dendritic branches and total length of apical and basal dendrites after acupuncture. These results suggest that acupuncture improves spatial learning and memory ability of middle-aged SAMP8 mice by ameliorating dendritic structure.