摘要
目的:探索蒲公英总黄酮对Aβ_(25-35)诱导的阿尔茨海默病(AD)大鼠记忆功能的影响以及潜在机制。方法:将50只健康SD大鼠随机分为正常对照组、模型组和蒲公英总黄酮低、中、高剂量组(100、200、400 mg·kg-1)。采用大鼠右侧海马CA1区注射1μL Aβ_(25-35)建立AD大鼠模型,术后各组进行灌胃治疗21d。治疗结束采用Morris水迷宫法观察大鼠的记忆能力;分离海马组织并制备组织匀浆,采取二氯二氢荧光素-乙酰乙酸酯(DCFH-DA)荧光法检测活性氧(ROS)水平;利用硫代巴比妥酸法和黄嘌呤氧化酶法检测丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性;将海马组织制备切片,应用TUNEL染色观察海马神经元凋亡; Western blot法检测凋亡相关基因Bcl-2、Bax和Caspase-3的蛋白表达。结果:与正常对照组相比,模型组大鼠逃逸潜伏期明显延长,空间探索时间明显缩短,海马组织ROS水平增加,MDA含量明显增高,SOD活性明显下降,海马神经元细胞凋亡增加,Bax和Caspase-3表达上调同时Bcl-2表达降低。与模型组相比,不同浓度的蒲公英总黄酮均能缩短逃逸潜伏期,延长空间探索时间,降低ROS水平和MDA含量,升高SOD活性,减少神经元细胞凋亡,同时上调Bcl-2表达,降低Bax和Caspase-3表达,并且呈现浓度依赖性关系。结论:蒲公英总黄酮能够保护Aβ_(25-35)诱导的大鼠记忆能力损伤,这可能与拮抗氧化应激介导的神经元细胞凋亡有关。
Objective:To study the influence and potential mechanism of total flavonoids from dandelion on memorizing ability in rat models of Aβ_(25-35)-induced Alzheimer disease.Methods:Healthy SD rats(n=50) were randomly divided into five groups.Aβ_(25-35)(1μL) was injected into hippocampus CA1 region to establish AD model.Then,rats were treated with intragastric total flavonoids from dandelion(100,200 and 400 mg·kg-1) for 21 days.Memory abilities were assessed by Morris water maze.One side of hippocampus was prepared to brain tissue homogenate.Reactive oxygen species(ROS) level was measured by DCFH-DA fluorescence assay.The MDA content and SOD activity were detected respectively by the thiobarbituric method and xanthinoxidase method.The other side of hippocampus was prepared to cerebral frozen section.Hippocampus neuronal apoptosis was observed by TUNEL,Western blot was used to detect expressions of apoptosis-related protein Bcl-2,Bax and Caspase-3.Results:Compared with control group,escape latency was significantly increased,spatial exploring time was significantly reduced,hippocampus ROS level was significantly increased,MDA contents was significantly increased,SOD activity was obviously decreased,the rate of hippocampus neuron apoptosis was significantly increased,meanwhile the protein expression of Bcl-2 was inhibited,the protein expression of Bax and Caspase-3 were increased in model group.Compared with model group,escape latency was significantly reduced,spatial exploring time was significantly increased,hippocampus ROS level was significantly decreased,MDA contents was significantly decreased,SOD activity was significantly increased,and rate of hippocampus neuron apoptosis was significantly reduced.Furthermore,the protein expression of Bcl-2 was increased,while the protein expression of Bax and Caspase-3 were decreased in a dose-dependent manner.Conclusion:Total flavonoids from dandelion had protective effect on memory impairment induced by Aβ_(25~35),which may be related with the inhibition on oxidative stress-mediated apoptosis.
引文
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