荔枝核提取物对D-半乳糖诱发小鼠学习记忆损伤的保护机制

The Protecting Machanism of Litchi Seed Aqueous Extracts on Learning and Memory Damage Induced by D-galactose in Mice

目的探讨荔枝核提取物（Litchi Seed Aqueous Extracts，LSAE）对D-半乳糖诱发小鼠学习记忆障碍的改善作用及其机制。方法50只KM小鼠随机分为空白组、模型组、石杉碱甲组（HU，0．4mg·kg^-1·d^-1）、LSAE低剂量（15g·kg^-1·d^-1）和高剂量（60g·kg^-1·d^-1）剂量组。上述动物除空白组外，均连续8周皮下（sc）注射D．半乳糖（500mg·kg^-1·d^-1），并于第5周起分别灌胃相应药物。采用Morris水迷宫测试小鼠学习和记忆能力，用流式细胞仪测小鼠脑组织线粒体膜电位，采用RT—PCR方法测凋亡基因bcl-2mRNA、baxmRNA及B淀粉样前体蛋白（β-APP）mRNA的表达。结果LSAE可明显改善模型小鼠的学习和记忆能力，提高脑细胞线粒体膜电位，增强抗凋亡基因bcl-2mRNA表达，降低促凋亡基因baxmRNA含量，同时下调脑组织B-APPmRNA的表达。结论LSAE具有改善D-半乳糖诱发小鼠学习记忆障碍的作用，其作用机制可能与其提高脑细胞内线粒体膜电位，抑制细胞凋亡和下调淀粉样前体蛋白D—APP的表达有关。

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 m·kg^-1·d^-1） group and Litchi Seed Aqueous Extracts （15 g·kg^-1·d^-1, 60 g·kg^-1·d^-1） groups, 10 mice in each group. D-galactose （500 m·kg^-1·d^-1） 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（[3-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 mem- brane potential, suppressing apoptosis and down regulation of the [^-APP mRNA expression in the brain tissue.