ABSTRACT
OBJECTIVE Lychee seed, a famous traditional Chinese medicine, recently were reported to improve the learning and memory abilities in mice. However, it is still unclear whether lychee seed saponins (LSS) can improve the cognitive function and associated mechanisms. METHODS In present studies, we established the Alzheimer disease (AD) model by injecting Aβ25-35 into the lateral ventricle of rats. Then the spatial learning and memory abilities of LSS- treated rats were evaluated with the Morris water maze, meanwhile the protein expressions of AKT, GSK3β and Tau in the hippo?campal neuron were analyzed by immunohistochemistry and Western blotting. RESULTS The results showed LSS can improve the cognitive functions of AD rats through shortening the escape latency, increasing the number across the platform, platform quadrant dwell time and the percentage of the total distance run platform quadrant. The protein expression of AKT was significantly up-regulated and that of GSK3β and Tau were decreased remarkably in the hippocampal CA1 area. CONCLUSION Our study is the first to show that LSS significantly improve the cognitive function and prevent hippocampal neuronal injury of the rats with AD by activation of the PI3K/AKT/GSK3β signaling pathway, suggesting LSS may be developed into the nutrient supplement for the treatment of AD.