以β-淀粉样蛋白为靶标的藏药对阿尔采末病Tg2576转基因鼠学习记忆的影响

Tibet-medicine effects on β-amyloid pathology in a transgenic mouse model of Alzheimer's disease

目的探讨藏药七十味珍珠丸(RNSP)以β-淀粉样蛋白为靶标对阿尔采末病(AD)动物模型学习记忆作用的机制。方法25只13～14mon♀Tg2576转基因鼠和同龄♀C57BL/6XDBA鼠为正常对照组给予七十味珍珠丸灌胃8wk。利用Y-迷宫明暗分辨学习和旷场实验观察转基因鼠学习、记忆和行为学变化。蛋白免疫印迹法测定鼠血清β淀粉样蛋白(Aβ)和β位点APP内切酶(BACE-1)含量,免疫组织化学法观察Aβ在脑的表达。结果通过Y-迷宫测试,藏药Tg2576治疗组达标所需要的训练时间明显低于Tg2576对照组(P<0.01)。旷场实验测定发现Tg2576治疗组在中央格停留时间明显减低,跨格和站立次数增加,粪便颗粒数也明显减少。蛋白印迹法定量分析,经RNSP治疗的转基因鼠血清Aβ和BACE-1含量较对照组明显减低。RNSP能够明显减少大脑皮层和海马周围老年淀粉样斑块的数目和面积。结论藏药七十味珍珠丸改善Tg2576转基因鼠学习和空间记忆以及探索运动能力,减少焦虑状态等认知行为可能通过抑制BACE-1(即β-分泌酶)的表达来减少老年斑和Aβ的生成而起作用的。

Aim To investigate the effect of Ratanasampil （RNSP）, a traditional Chinese Tibet medicine on the β-amyloid peptide as a therapeutic target in Alzheimer＇s disease. Methods 25 mice of β- 14 months old female Tg2576 and C57BL/6XDBA control mice were used in drug test. All mice sacrificed after 8 weeks of RNSP treatment at 15 - 16 months of age. Open field activity and Y-maze tests were performed for animal behavioral change and memory ability. The serum levels of β-amyloid （Aβ） peptides and beta-site amyloid precursor protein cleaving enzyme-1 （BACE- 1 ） were measured by Western blot. Immunostaining with 1 Eβ （1 ： 25 ） was carried out on brain sections of drug and vehicle-treated mice. Results Drug-treated Tg2576 mice decreased training time by Y-maze tests （P 〉 0. 01 ）. Two months RNSP treatment in Tg2576 mice caused a decrease in open field behavior. The level of Aβ and BACE-1 in the serum was significantly decreased after RNSP treatment （ P 〈 0.01 ）. Preliminary plaque counting of the sections showed reduced plaque numbers in the drug-treated mice in brain. Conclusions Ratanasampil can improve the learning and memory ability of Tg2576 mice. It may reduce beta-amyloid generation by directly inhibiting BACE-1 activity.