Effect of hyperforin on learning and memory abilities and Aβ1-42, βAPP and BACE1 protein expressions in hippocampus of Alzheimer's disease model mice

To investigate the effect of the hyperforin (HF) on learning and memory function and Aβ₁₋₄₂, βAPP and BACE1 protein expressions in hippocampus of five-month-old APP/PS1 double transgenic mice, and discuss the underlying mechanism of HF. The five-month-old APP/PS1 double transgenic mice were randomly divided into the model group, rosiglitazone group (12 mg•kg⁻¹•d⁻¹) and HF high dose, middle dose and low dose groups (600, 300 and 150 mg•kg⁻¹•d⁻¹) in each group; in addition, 15C57BL/6J mice with the same months and background were selected as normal group. Drugs were diluted in the same volume before using, and then administrated by ig for 7 months, 1 time a day; the mice in normal group and model group received the same volume of distilled water. The learning and memory ability was tested by Morris water maze; Aβ₁₋₄₂, βAPP and BACE1proteinexpressionlevelswere tested by immunohistochemistry and Western blot. The Morris water maze results showed that as compared with the normal group, the learning and memory ability was significantly impaired in mice of model group (P<0.01); as compared with the model group, the learning and memory ability was improved in mice of rosiglitazone group and HF high, middle and low dose groups(P<0.01 or P<0.05). Immunohistochemistry and western blot results showed thatas compared with the normal group, the Aβ₁₋₄₂, βAPP and BACE1 protein expression levels in hippocampus were significantly increased in mice of model group (P<0.01);as compared with the model group, Aβ₁₋₄₂, βAPP and BACE1 protein expression levels in hippocampus were decreased in mice of rosiglitazone group and HF high, middle and low dose groups (P<0.01 or P<0.05). HF may improve the learning and memory ability of AD model mice via inhibition of βAPP and BACE1 protein expressions, thus reduced the generation of Aβ₁₋₄₂ proteins and amyloid plaque deposits in the brain.