Objective: To observe the effects and mechanisms of Yizhi capsule on beta-amyloid protein 1-42 (Aβ1-42)induced learning memory disorders and cholinergic system in rat Alzheimer's disease(AD) model. Method: The SD rats were randomly divided into seven groups

single dose normal saline(NS

5 μL) was given via right hippocampus injection to sham group

single dose Aβ1-42(2 g·L-1) 5 μL was given via right hippocampus injection to model group and the treatment groups were orally given Yizhi capsules for one month. After 21 days of administration

Morris water maze was used to measure learning and memory performance.The rats of treatment groups were given Yizhi caspase for 10 days. After the watermaze experiment

biochemical detection choline acetyltransferase (ChAT) and acetylcholinesterase (AchE) activity were measured.The protein expressions of Aβ

P-tau(S262) were determined by Western blot method. Result: Compared with normal group

and in the total distance and escape latency sham group had no difference. Compared with sham group

in model group the total distance and escape latency were significantly prolonged

and differences was statistically significant(P<0.01). Compared with model group

in other groups the total distance and escape latency were significantly shorten(P<0.05

P<0.01)

the AchE of enzymeactivity was significantly lower and increased ChAT enzyme activity

the phosphorylation of Aβ1-42and Tau at Ser262 were decreased in other groups. Conclusion: Yizhi capsule can attenuate the learning and memory impairment induced by Aβ1-42

which maybe related to increasing the cholinergic system of the central nervous system and suppressing Tau protein.