Objective: To observe the effect of acupuncture stimulation of bilateral "Hegu" (LI 4) and "Taichong" (LR 3, the so-called "Four Gate Points") on learning-memory ability, hippocampal interleukin-1 (IL-1) P and IL-2 and amyloid beta (Abeta) 42 levels in Alzheimer's disease (AD) rats,so as to reveal its underlying mechanism in improving AD.
Methods: Male SD rats were randomly divided into sham operation, model, medication and acupuncture groups (n = 12 rats in each group). The AD model was created by microinjection of streptozotocin (10 pL, 3 mg/kg) into the lateral ventricle (repeated the microinjection once two days later). Bilateral LR 3 and LI 4 were punctured with filiform needles and stimulated manually, once a day, 6 days a week for 4 weeks. The rats of the medication group were intragastric perfusion of Donepezil HOI (0.045 mg/kg), once a day for 4 weeks. The learning-memory ability was detected by Morris water maze swimming tests. The immunoactivity of hippocampal Abeta 42 was detected by immunohistochemistry, and the contents of IL-1 P and IL-2 in the hippocampus tissue were determined by ELISA.
Results: After modeling, the average escape latency of Morris water navigation task was significantly increased, and the target-platform crossing times of space probe trials were significantly reduced in the model group (P<0.05), suggesting a g-memory ability. After acupuncture intervention, the increased escape latency and the decreased target-platform crossing times were reversed, suggesting an improvement of the learning-memory. The hippocampal Abeta 42 immunoactivity and IL-1 beta content were significantly higher in the model group than in the sham operation group (P<0.05), but the hippocampal IL-2 content was markedly decreased in the model group (P<0. 05). Following the interventions, the increased Abeta 42 expression and IL-1 beta contents, and the decreased IL-2 contents in the hippocampus were also reversed in both the acupuncture and medication groups (P<0.05).
Conclusion: Acupuncture may improve learning-memory ability in AD rats, which may be associated with its effects in reducing hippocampal Abeta13 42 expression and IL-1beta content and in up-regulating IL-2 level.