Objective To observe the effect of electroacupuncture(EA) of "Xiusanzhen"[3 acupoints

i.e.

bilateral "Yingxiang"(LI 20) and "Yintang"(EX-HN 3)] on expression of B-cell lymphoma/leukemia-2(Bcl-2

an antiapoptosis protein) and Bax(a protein for promoting apoptosis) in the hippocampus in Alzheimer disease(AD)rats

so as to explore its clinical mecha-nisms underlying relieving AD.Methods A total of 40 Sprague Dawley rats were randomly divided into normal control

AD mo-del

EA and olfactory nerve transaction(ONT)+EA groups

with 10 rats in each.AD model was established by injection of β-amyloid(Aβ)1-40(2 μL containing 10 μg) into the hippocampus(Bregma: 3.5 mm

L: 2.0 mm

H:-2.8 mm below dura)

and the ON was sectioned by using a fine needle.EA(80-100 Hz

1-3 mA) was applied to bilateral LI 20 and EX-HN 3 for 10 min

once daily(except Saturdays and Sundays) for 6 weeks.The expression of Bcl-2 and Bax of hippocampus was measured by immunohistochemistory.Results Compared with the normal control group

the expression of Bcl-2 of hippocampus was significantly lower in the AD model group(P<0.05)

and that of Bax in AD model group was much higher(P<0.01).In comparison with the model group

the expression of hippocampal Bcl-2 was up-regulated significantly(P<0.01)

and that of hippocampal Bax protein down-regulated considerably in the EA group(P<0.01).No significant differences were found between AD model and ONT+EA groups in the expression of hippocampal Bcl-2 and Bax proteins(P>0.05)

suggesting a necessary premise condition for EA in regulating hippocampal Bcl-2 and Bax expression.Conclusion "Xiusanzhen" can regulate the expression of hippocampal Bcl-2 and Bax proteins in AD rats

which may contribute to its clinical effect in relieving AD

and the therapeutic effect depends on the integrity of the olfactory nerve pathway.