RESUMEN
Objective To study the effect of Eclipta alba on learning and memory ability and brain derived neurotrophic factor(BDNF) in brain of Alzheimer's disease (AD) model rats.Methods Healthy adult SD rats were randomly divided into control group,model group,low dosage group and high dosage group.There were 10 rats in each group.The model of Alzheimer's disease was established with subcutaneous injection of D-galactose and microinjection Aβ25-35 on bilateral hippocampus.All rats were treated with saline solution or different dosage of Eclipta alba respectively lasting 8 weeks.Then the ability of learning and memory of AD rats was evaluated by the Morris water maze test.The levels of expression of BDNF in brain were determined by immunohistochemical staining method and Western Blot method.Results The Morris water maze test:the average escape latent period prolonged besides the percentage of the swimming time in the target quadrant from the total swimming time and the times across the platform((34.14± 1.43) s,(33.71±3.82) ％,(3.40±0.70) times) decreased significantly in model group compared with control group((18.83±0.62) s,(41.98±3.96) ％,(5.40± 1.17) times,P＜0.01).The average escape latent period shortened besides the percentage of the swimming time in the target quadrant from the total swimming time and the times across the platform increased significantly in high dosage group compared with the model group (P＜0.01).Immunohistochemical staining and Western blot:the level of expression of BDNF in brain in model group was prominently less than control group (P＜ 0.01).The BDNF level in drug treated groups was prominently higher than model group(P＜0.01).The expression of BDNF increased with the drug dosage increasing.Conclusion Eclipta alba can improve the learning and memory function of AD rats by enhance the expression of BDNF.