雷公藤甲素抑制APP/PS1双转基因AD模型小鼠海马内Aβ沉积和老年斑形成

Triptolide inhibits the Aβ deposition and senile plaques formation in the hippocampus of APP/PS1 double transgenic mice

目的研究雷公藤甲素（T10）对APP/PS1双转基因AD模型小鼠（APP/PS1dtg）β-淀粉样蛋白（Aβ）沉积与老年斑（SP）形成的影响。方法取18只4.5月龄健康雄性APP/PS1dtg,随机分为3组,分别以T10灌胃：5μg/（kg·d）（T10 H组）、1μg/（kg·d）（T10 L组）和等容量的溶媒灌胃（PLC组）,共计45d。45d后取材,左侧半大脑切片,6E10免疫组织化学方法染色和刚果红染色结合无偏性体视学定量分析,研究T10对海马Aβ沉积和SP形成的影响;分离右侧半海马,免疫印迹法分析海马Aβ蛋白水平的变化。结果与PLC组比较,T10 H组海马6E10阳性的Aβ沉积总面积减少了35%（P〈0.001）,SP总面积减少了32%（P〈0.001）;T10 L组海马Aβ斑总面积减少了18%（P〈0.05）,SP总面积减少了21%（P〈0.05）;T10呈剂量依赖性抑制Aβ在APP/PS1dtg海马的沉积和SP的形成,减少海马内Aβ蛋白水平;免疫印迹分析也显示,T10 H组海马Aβ蛋白水平最低,PLC组Aβ蛋白水平最高,T10L组Aβ蛋白水平介于两者之间。结论T10抑制Aβ的产生和SP形成,或可用于AD的治疗。

Objective To examine the effects of Triptolide （T10） on the Aβ deposition and senile plaques formation in the hippocampus by using the APP/PS1 double transgenic mice model of AD （APP/PS1dtg）. Methods Eighteen Male APP/PS1dtg mice aged at 4.5 months were used in this study. The mice were divided into 3 groups randomly, High- 5μg/（kg· d） T10 （T10 H, n = 6）, Low- 1μg/g（kg·d） T10 （T10 L, n = 6） and placebo （PLC, n = 6）. Intraperitoneal administration of T10 and capacity solvents （PLC group） was given in a period of a total of 45days. After 45days of treatment, the mice were sacrificed and the brains removed for processing. The brains were separated along the middle sagittal sulcus. The left side was used for the histological study staining 6E10 immunohistochemical and Congo red methods, and quantitative analysis by unbiased stereological counting. The right hippocampus was dissected, Western blotting was performed to assess the change of protein level for Aβ. Results Compared with the PLC group, the total area of 6E10 positive Aβ plaques in the hippocampus of T10 H was reduced by 35 % （ P 〈 0. 001 ）, and that of T10 L reduced by 18 % （ P 〈 0.05） ; and the total area of SP in the hippocampus of T10 H group was reduced by 32% （P 〈 0.001 ）, and in the T10 L reduced by 27% （P 〈 0.05）. Western blotting protein analysis also displayed that T10 H group Aβ protein levels in the hippocampus was lowest, Aβ protein levels in PLC group was highest, and Aβ protein levels in T10 L group was moderate. Conclusion T10 may be useful in AD treatment via inhibiting Aβ production and SP formation.