远志皂苷通过UPP通路清除AD大鼠脑神经细胞代谢废物积聚的作用机制研究  

The Mechanism of Tenuigenin for Eliminating Waste Product Accumulation in Cerebral Neurons of Alzheimer's Disease Rats via Ubiquitin-Proteasome Pathway

作　　者：陈勤[1] 陈逸青[2] 叶海燕[1] 于剑奇 施其权[1] 黄炎[1] 

机构地区：[1]安徽大学生命科学学院,安徽省中药研究与开发重点实验室,合肥230601 [2]德国海德堡大学曼海姆医学院,德国曼海姆68167

出　　处：《中国中西医结合杂志》2015年第3期327-332,共6页Chinese Journal of Integrated Traditional and Western Medicine

基　　金：安徽省教育厅自然科学研究项目(No.KJ2009A116;KJ2012A031);教育部大学生创新性实验项目(No.201210357043);安徽大学大学生科研训练计划项目(No.2013024);省级精品课程项目(No.2009024)

摘　　要：目的探讨远志皂苷(tenuigenin,TEN)对AD大鼠脑内β淀粉样蛋白(amyloidβprotein,Aβ)沉积、异常磷酸化Tau浓度积聚的清除作用及其作用机制。方法大鼠右侧海马CA1区注射Aβ1-40建立AD模型,透模成功的大鼠分为模型组、TEN低、中、高剂量组,并用远志皂苷(18.5、37.0、74.0 mg/kg)对大鼠进行灌胃治疗,另设假手术组;免疫组织化学法观察大鼠脑海马神经元中Aβ621-40、Tau p-Ser2蛋白的表达;Western blot检测大脑神经元中泛素蛋白(ubiquitin,Ub)和泛素连接酶E3(ubiquitin-protein ligase E3)的表达水平。ELISA法检测大脑神经元中26S蛋白酶体的含量。结果免疫组化显示,与假手术组比较,模型组大鼠海马神经元中Aβ、Tau p-Ser262蛋白阳性反应的神经元数量显著增多(P<0.01);Western blot检测显示,与假手术组比较,模型组大鼠脑组织中Ub表达水平上调,而E3表达下调(P<0.01)。ELISA检测显示,AD大鼠脑内的26S蛋白酶体含量显著减少(P<0.01)。与模型组比较,TEN各组大鼠海马神经元中Aβ1-40、Tau p-Ser262和Ub表达水平下降明显,泛素连接酶E3表达水平和26S蛋白酶体含量也明显升高,以37.0 mg/kg和74.0 mg/kg剂量组效果最佳(P<0.05,P<0.01)。结论 UPP通路参与了AD的发生过程,远志皂苷能明显降低AD大鼠脑内Aβ1-40沉积和tau异常磷酸化水平。Objective To explore the scavenging action of tenuigenin （TEN） on intracerebral amyloid β protein （Aβ） aggregation and the abnormal phosphorylated tau protein and its mechanism in Alzheimer＇s disease （AD） rats＇ brain. Methods Aβ_1-40 was injected into the right CA1 region hippocam- pus to establish the AD model. Successfully modeled rats were divided into the model group, the low, middle, high TEN group. Rats were administered with TEN （18.5, 37.0, 74.0 mg/kg） by gastrogavage. Besides, a sham-operation group was set up. Expression levels of Aβ_1-40and Tau p-Ser^262 were detected by immunohistochemistry. Expression levels of ubiquitin （Ub） and Ub-protein ligase Es were measured by Western blotting. The content of 26S proteasome was detected by ELISA. Results Immunohistochem- ical results showed that the number of Aβ and Tau p-Ser^262 positively reacted neurons significantly in- creased in model group, when compared with the sham-operation group （P 〈0.01 ）. Results of Western blot showed expression levels of ubiquitinated protein were up-regulated and those of Ub-protein ligase Es were down-regulated in the model group （P 〈0.01 ）. ELISA results showed that the content of 26S protea- some significantly decreased in AD rats＇ brain （P 〈0.01 ）. Compared with the model group, expression levels of Aβ_1-40, Tau p-Ser^262, and Ub significantly decreased; expression levels of Ub-protein ligase E_3 apparently increased ; the content of 26S proteasome significantly increased in each TEN treatment group （P 〈0.05,P 〈0.01）. Best effect was shown in 37.0 mg/kg and 74.0 mg/kg TEN groups. Conclusions Ub proteasome pathway （UPP） participated in the occurrence of AD. TEN could obviously reduce intracere- bral Aβ_1-40 accumulation and abnormal tau phosphorylation.

关 键 词：远志皂苷 老年性痴呆 Β-淀粉样蛋白 TAU蛋白磷酸化 泛素蛋白酶体通路 代谢废物积聚 

分 类 号：R285.5[医药卫生—中药学]