Objective To observe the effect of acupuncture and moxibustion(AM)on learning-memory ability and expression of amyloid beta(Aβ)in the hippocampal dentate gyrus(DG)of Alzheimers disease(AD)rats

so as to explore its mechanism underlying improvement of AD. Method Forty male Wistar rats were randomly divided into normal

sham operation

model and AM groups(n=10 in each).The AD model was established by bilateral hippocampal injection of Aβ_(1-42)(5 μL).The AM was applied at"Baihui"(GV 20)and"Shenshu"(BL 23)for 15 min

once daily for 12 times.Morris water maze tests were used to assess the rats' learning-memory ability.The levels of serum Aβ_(1-42) and Aβinternalizing enzymes including transthyretin(TTR)

lipoprotein lipase(LPL)

alpha 2 macroglobulin(α_2 M)and apolipoprotein E(ApoE)were detected by ELISA.The expression of Aβ_(1-42) in the hippocampal DG was detected by immunohistochemistry.Results Compared with the sham operation group

the average escape latency of location navigation test was significantly prolonged in the first 5 days and the last 3 days(P<0.01)

and the residence time of the target-quadrant and the platform crossing times of special probing task were significantly reduced in the model group(P<0.01).After the intervention

the average escape latency was obviously shortened in the first 5 days and the last 3 days(P<0.01)

and both the residence time and the platform crossing times were significantly increased in the AM group relevant to the model group(P<0.01

P<0.05).After modeling

the contents of TTR

LPL

α_2 M and ApoE in the serum were significantly lower in the model group than in the sham operation group(P<0.01

P<0.05)

while the levels of serum Aβ_(1-42) and hippocampal Aβ_(1-42) expression were considerably increased relevant to the sham operation group(P<0.01).Following the intervention

the TTR

LPL

α_2 M and ApoE contents in the serum were significantly increased(P<0.01

P<0.05)

and both serum Aβ_(1-42) and hippocampal Aβ_(1-42) expression were notably down-regulated in comparison with the model group(P<0.05).No significant differences were found between the normal and sham operation groups in the levels of all the abovementioned indexes(P>0.05).Conclusion AM can improve the learning-memory ability of AD rats

which may be related to its effects in up-regulating the contents of serum Aβinternalizing enzymes and promoting the clearance of hippocampal Aβ.It suggests a protective role of AM on hippocampal neurons.