Abstract: Objective: To explore the influence of total alkaloids of Corydalis Ochotensis(TAOCO) on the behavior and pathomorphology of brain tissue of the rats with Alzheimer's disease(AD) induced by β-amyloid protein 25-35(Aβ_25-35),and to clarify its therapeutic effects on the AD rats. Methods: The Wistar rats were divided into mormal control group(treated with 0.5 mL·100 g^-1 distilled water)(n=9),model group(treated with 0.5 mL·100 g^-1 distilled water)(n=9),positive drug group(treated with 1.75 mg·kg^-1 donepezil hydrochloride)(n=9), and low,middle and high doses (treated with 2.0,4.0 and 8.0 mg·kg^-1) of TAOCO groups(n=8,n=9,n=9).The rat AD models were made by injecting Aβ_25-35 into hippocampus.On the 14th day after operation,the rats were administered for 7 d.Morris water maze test was used to detect the spatial learning and memory ability of the rats;dark avoidance task was used to observe the passive avoidance ability of the rats; the pathomorphology of the cerebral cortex and hippocampus of the rats were detected. Results: The Morris water maze test results showed that compared with model group,the latency to platform of the rats in low dose of TAOCO group was decreased on the 4th and 5th days(P<0.05); the latency and swimming distance to reach the platform of the rats in middle dose of TAOCO group were decreased on the 5th day(P<0.05),and the starting angle of the rats was reduced on the 3th day(P<0.05); the latencies to reach the platform of the rats in high dose of TAOCO group were decreased on the 2nd and 5th days(P<0.05),and the starting angle of the rats was decreased on the 6th day(P<0.01). Compared with model group,on the 7th day,the time of staying on platform,distance of staying on platform,time of staying on platform/total time,distance of staying on platform/total distance of the rats in different doses of TAOCO groups were all increased significantly(P<0.05) within 1.5 min.Compared with model group,the times of crossing platform and time of staying in effective area of the rats in low and high doses of TAOCO groups were significantly increased(P<0.05).The dark avoidance task results showed that compared with model group,the error latencies and the error times of the rats in different doses of TAOCO groups had no significant differences on the 2nd day(P>0.05).Compared with model group,there was no obvious improvement of the cerebral cortex and hippocampus injury of the rats in low and middle doses of TAOCO groups.In high dose of TAOCO group,the cerebral cortex and hippocampus injury of the rats were significantly improved. Conclusion: TAOCO can improve the learning and memory function of the AD rats and reduce the pathological injury of brain tissue of AD rats.

Key words: amyloid β-protein, total alkaloids of Corydalis Ochotensis, rats,Wistar, Alzheimer's disease