Abstract: Objective To investigate the protecting machenism of Litchi Seed Aqueous Extracts on the learning and memory obstacles induced by D-galactose-induced in mice. Methods Fifty KM mice were randomly divided into normal group, model group, Huperzine A (0.4 mg·kg^-1·d¹) group and Litchi Seed Aqueous Extracts (15 g·kg^-1·d¹, 60 g·kg^-1·d¹) groups, 10 mice in each group. D-galactose (500 mg·kg^-1 ·d¹) were injected to all mice for 8 consecutive weeks by subcutaneous injection except normal group. At the beginning of 5 weeks, all drugs were given by gavage for 4 weeks. Water maze was used to detect the spatial learning and memory. The mitochondrial membrane potential were recorded with flow cytometer (FCM); the expressions of bcl-2 mRNA, bax mRNA and amyloid beta-protein precursor(β-APP mRNA) in the brain tissue were assayed by reverse transcription polymerase chain reaction. Result Litchi Seed Aqueous Extracts could obviously improve the condition of learning and memory obstacles in model mice. And it could significantly enhanced the mitochondrial membrane potential, reduced the expressions of bax mRNA and β-APP mRNA, increased the expression of bcl-2 mRNA. Conclusion Litchi Seed Aqueous Extracts possesses improving the learning and memory obstacles induced by D-galactose in mice which may be concerned with its enhancing the mitochondrial membrane potential, suppressing apoptosis and down regulation of the β-APP mRNA expression in the brain tissue.

Key words: Litchi Seed Aqueous Extracts, D-galacitose, learning and memory, antioxidative, apoptosis