Objective To explore the effect of electroacupuncture(EA) on the ability of spatial learning-memory and the expression of IL-1β

IL-6 and TNF-α in the hippocampus and spleen tissues and the number of hippocampal neurons and spleen lymphocytes in Alzheimer's disease(AD) mice

so as to study its mechanisms underlying improvement of AD. Methods Twenty-four SAMP8 mice were randomly and equally divided into AD model

EA and medication groups

and 8 SAMR1 mice were used as the control group. EA(2 Hz

0.1 mA) was applied to "Baihui"(GV20) and "Yintang"(EX-HN3) for 20 min in the EA group

and intragastric administration of donepezil hydrochloride(0.92 mg/kg) was applied in the medication group

once daily for 15 d. The learning-memory ability was determined by Morris water maze task

and the histopathological changes of hippocampus were observed after H.E. staining

followed by determining neurons and the number of splenic lymphocytes. The expression levels of IL-1β

IL-6 and TNF-α in the hippocampus and spleen were detected by immunohistochemistry and Western blot

respectively. Results After mode-ling

the escape latency of place navigation test in the Morris water maze

the spleen index

immunoactivity and expression levels of IL-1β

IL-6 and TNF-α proteins in the hippocampus and spleen tissues were significantly increased(P<0.05

P<0.01). Compared with the model group

the escape latency

spleen index

immunoactivity and expression levels of IL-1β

IL-6 and TNF-α proteins in both hippocampus and spleen were significantly down-regulated in the medication(except the escape latency) and EA groups(P<0.01

P<0.05). The effect of EA was evidently superior to that of medication in shortening the escape latency

lowering the spleen index

and immunoactivity of hippocampal IL-6 and splenic TNF-α immunoactivity(P<0.01

P<0.05). Outcomes of H.E. staining showed disordered arrangement of neurons with nuclear pyknosis or apoptosis in partial neurons in the hippocampus

and thickened and swollen spleen capsule tissue with loose structure and an increased number of lymphocytes in the model group

which was relatively milder in the EA and medication groups. Conclusion EA can improve the learning-memory ability of AD mice

which may be associated with its effect in relieving the inflammation reaction in the hippocampus and spleen tissues.