Protective effect of tenuigenin on impaired learning and memory in rats with Aβ_(1-40)-induced AD

Objective:To determine the effect of tenuigenin(TEN) on learning and memory and the possible mechanisms in rat model of Aβ 1-40-induced AD.Methods:Healthy SD rats(n = 50) were randomly divided into five groups.Aβ 1-40(1 μL) was injected into hippocampus CA1 region to establish AD model.Then,rats were treated with intragastric TEN(18.5,37.0 and 74.0 mg·kg-1) for 30 days.Learning and memory abilities were assessed by Morris water maze; the apoptotic rates of hippocampal neurons were examined by flow cytometry; the expressions of apoptosis-related proteins(Bcl-2,Bax,Cyt-c and caspase-3) in hippocampal neurons were measured by Western blotting.Results:Compared with AD control,TEN significantly increased the abilities of learning and memory(P 0.01),reduced apoptotic rate of hippocampus neurons(P 0.01),markedly decreased the levels of Bax,Cyt-c and caspase-3,and increased the expression of Bcl-2(P 0.05 or 0.01).Conclusion:TEN can improve the learning and memory function of AD rats through regulating the ratio between Bax and Bcl-2,blocking Cyt-c release,reducing caspase-3 expression and counteracting Aβ-induced neuronal apoptosis in the hippocampus.