Aβ 42与Aβ 42寡聚体的生物学性质比较研究  

Study of biologic characters of Aβ42 and Aβ42 oligomer

作　　者：王建秀[1] 王德生[1] 段淑荣[1] 赵敬堃[1] 王景贺[2] 

机构地区：[1]哈尔滨医科大学第一临床医学院神经内科,黑龙江哈尔滨150001 [2]哈尔滨工业大学精密仪器研究所,黑龙江哈尔滨150001

出　　处：《中国现代医学杂志》2009年第17期2577-2580,2584,共5页China Journal of Modern Medicine

基　　金：国家自然科学基金资助项目(No:30670726)

摘　　要：目的比较Aβ42和Aβ42寡聚体的细胞毒性。应用原子力显微镜(AFM)观察比较Aβ42和Aβ42寡聚体的聚集状态。方法应用MTT检测Aβ42和Aβ42寡聚体的细胞毒性;TUNEL法测定Aβ42和Aβ42寡聚体的细胞凋亡作用。制备终浓度为50μmol/L的Aβ42寡聚体和Aβ42溶液。在云母片上制作Aβ样品,用原子力显微镜的轻敲模式观察不同时间、温度条件下的Aβ42寡聚体状态,比较Aβ42寡聚体与Aβ42聚集形态的差异。结果MTT、TUNEL结果表明Aβ42和Aβ42寡聚体均可降低PC12细胞的生存率,均有致细胞凋亡作用。10μmol/LAβ42寡聚体较20μmol/LAβ42能引起更多细胞凋亡,凋亡率差异有显著性(P<0.05)。4℃、48h内经HFIP作用的Aβ42以单体、寡聚体形式存在;室温、72h时未经六氟丙醇作用的Aβ42以纤维聚集态存在。结论Aβ寡聚体是Alzheimer病神经细胞损伤过程中的重要因素。相同浓度Aβ42寡聚体较Aβ42细胞毒性大。Aβ42寡聚体纤维随时间延长,室温条件下更利于纤维聚集;Aβ42寡聚体与Aβ42相同条件下聚集状态完全不同。利用原子力显微镜可观察不同Aβ的聚集情况,AFM是研究Aβ的有效手段。[Objectives] To explore the role of cytotoxicity of Aβ42 and Aβ42 oligomer to PC12 cell. To study aggregation states of Aβ42 and Aβ42 oligomer with atomic force microscope. [Methods] PC12 ceils were treated with Aβ42 and Aβ42 oligomer. To detect cytoactive by MTT and neuronal apoptosis by microscopy and TdT-mediated dUTP-biotin nick end labeling （TUNEL） method. Aβ42 and Aβ42 oligomer solutions with final concentration of 50 μmol/L were incubated for AFM experiments. Different Aβ aggregations prepared on freshly cleaved mica were examined and compared by tapping mode AFM imaging under different time and temperature conditions. [ Results ] The evidence for neuron cytotoxicity were found by MTT and microscopy, but some early signs of neuronal apoptosis was found by TUNEL method. Significant increasing in apoptosis had been shown in Aβ42 oligomer group in analysis of TUNEL as compared with Aβ42 group （P 〈0.05）. AFM observed different aggregate states of Aβ42 under different time and temperature conditions. Aβ42 samples showed presence of soluble monomer and oligomer under 4℃ within 48 hours, while fibrillar structures under room temperature after 72 hours. [Conclusions] These data suggested neuronal apoptosis was involved in AD. Different Aβ segmental play different roles in this process. AFM studies suggested that Aβ oligomer was a key factor in the pathogenesis of Alzheimer＇s disease. Aβ42 fibers extent along with time and were prone to aggregate under room temperature. Aβ42 had different aggregate states under identical conditions. AFM was a powerful tool for Aβstudies under physiological conditions.

关 键 词：Β-淀粉样蛋白 寡聚体 原子力显微镜 ALZHEIMER病 

分 类 号：R749[医药卫生—神经病学与精神病学]