Humanin拮抗Aβ_(31-35)引起的培养皮层神经元胞内Ca^(2+)浓度升高  

Effects of humanin on elevation of intracellular calcium concentration induced by β-amyloid peptide_(31-35) in cultured cortical neurons

作　　者：李灵敏[1] 乔健天[2] 张策[2] 

机构地区：[1]山西医科大学病理学教研室,太原030001 [2]山西医科大学生理学教研室,太原030001

出　　处：《生理学报》2009年第2期127-131,共5页Acta Physiologica Sinica

基　　金：supported by the National Natural Science Foundation of China (No. 30572085);Natural Science Foundation of Shanxi Province; China (No. 2007011111)

摘　　要：β-淀粉样蛋白(β-amyloid protein,Aβ)在脑组织中的过多沉积与阿尔茨海默病(Alzheimer’s disease,AD)的发病密切相关。Aβ的毒性作用机制目前尚不明确,有研究认为扰乱细胞内钙稳态是其重要机制之一。Aβ31-35是一个小的Aβ活性片段,具有与完整肽链相同的神经毒作用。Humanin(HN)是一种存在于AD患者脑组织中具有神经保护作用的多肽,它能有效抑制Aβ诱发的神经元死亡。本研究应用Ca2+荧光成像技术,检测不同时间给予不同浓度的HN对Aβ31-35引起的培养皮层神经元[Ca2+]i升高的影响,探讨HN对Aβ31-35神经毒的抑制作用是否通过抑制Aβ31-35所致的细胞内钙稳态紊乱而实现。结果显示:HN(10μmol/L)预孵育10min部分抑制Aβ31-35(25μmol/L)所致的神经元[Ca2+]i的升高。当HN与Aβ31-35(25μmol/L)同时加入时,10μmol/L HN未能改变Aβ31-35(25μmol/L)引起的神经元[Ca2+]i升高的幅度,但可延迟[Ca2+]i的升高;而20μmol/L HN明显抑制了Aβ31-35(25μmol/L)引起的神经元[Ca2+]i的升高。以上实验结果提示,Aβ31-35引起神经细胞内钙稳态的紊乱是其神经毒作用机制之一;HN抑制Aβ31-35引起的神经元[Ca2+]i升高具有时间和剂量依赖性。The disruption of the intracellular Ca^2＋ homeostasis has been reported to be one of the mechanisms of β-amyloid （Aβ） neurotoxicity in Alzheimer＇s disease （AD）. Aβ31-35, a small active fragment of Aβ, is believed to possess the similar biological activities of full-length Aβ molecule. Humanin （HN） is a recently identified peptide that suppresses neuronal death initiated by AD-related insults. The present study was to investigate the effects of HN on Aβ31-35-induced elevation of [Ca^2＋]i in cultured cortical neurons by real-time fluorescence imaging technique using the Ca2＋-sensitive dye, Fura-2/AM. The elevation of [Ca^2＋]i was observed in cultured neurons exposed to Aβ31-35 （25 μmol/L） （F340/F380：1 042.56±83.54, compared with control group： 804.73±48.230, P〈0.05, n=10）. Pretreatment of HN （10 μmol/L） for 10 min significantly decreased the elevation of [Ca^2＋]i induced by Aβ31-35 （25 μmol/L） （F340/F380： 918.788±50.73, compared with Aβ3l-35 group, P〈0.05, n=10）. When neurons were treated with HN and Aβ31-35 simultaneously, HN（10μmol/L） could not change the elevation of [Ca^2＋]i induced by Aβ31-35 （F340/F380：1 036.68±88.96, compared with Aβ31.35 group, P〉0.05, n=10）, while HN （20 μmol/L） diminished the elevation of [Ca^2＋]i induced by Aβ31-35（25μmol/L） significantly （F340/F380： 898.56±76.46, compared with Aβ31-35 group, P〈0.05, n=10）. The findings imply that： （1） the disruption of the calcium homeostasis induced by Aβ31-35 is possibly the basis of the neurotoxicity of Aβ31-35 in cultured cortical neurons; （2） HN suppresses the elevation of [Ca^2＋]i induced by Aβ31-35 in a dose- and time-dependent manner.

关 键 词：阿尔茨海默病 β-淀粉样蛋白31-35 HUMANIN 胞内钙离子 

分 类 号：R749.16[医药卫生—神经病学与精神病学]