Objective: To study effect of compound rehmannia on expression of glial cell line-derived neurotrophic factor(GDNF) mRNA in hippocampus of rats with Alzheimer's disease (AD). Method: Forty healthy Wistar rats were screened by the Morris water maze

then the rats were divided 4 groups: the normal group

model group

western medicine group and traditional Chinese medication group randomly (n=10 each).The normal group was given tape water and routine food without any treatment. The remaining 3 groups were established with AD model induced by streptozotosin(STZ)

and the model group was not given any treatment after the model establishment. The rats in traditional Chinese medication group were orally given compound rehmannia 10 g·kg-1

and the rats in western medication group were orally given donepezil hydrochloride 0.4 g·kg-1 for a course of 4 weeks.The Morris water maze test was used to evaluate learning and memory ability in rats; and the expression of GDNF mRNA in hippocampus was detected by in situ hybridization and RT-PCR. Result: Compared with normal group

the learning and memory abilities in model group were lowered (P<0.05). After given compound rehmannia all the abilities were significantly improved (P<0.05). Compared with the normal group

GDNF mRNA in hippocampus in the model group was obviously decreased

the difference was marked (P<0.05). Compared with the model group

GDNF mRNA in the western medicine group and traditional Chinese medication group was obviously improved

the difference was marked (P<0.05). Conclusion: Compound rehmannia may protect the nerve in AD rats by improving the expression of GDNF mRNA in hippocampus.